making EXPLAIN extensible

From f10ecb8178c99084710bee29fa5de0c4d6ee2406 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 21 Feb 2025 11:48:32 -0500
Subject: [PATCH v2 2/3] Add some new hooks so extensions can add details to
 EXPLAIN.

Specifically, add a per-node hook that is called after the per-node
information has been displayed but before we display children, and a
per-query hook that is called after existing query-level information
is printed. This assumes that extension-added information should
always go at the end rather than the beginning or the middle, but
that seems like an acceptable limitation for simplicity. It also
assumes that extensions will only want to add information, not remove
or reformat existing details; those also seem like acceptable
restrictions, at least for now.

If multiple EXPLAIN extensions are used, the order in which any
additional details are printed is likely to depend on the order in
which the modules are loaded. That doesn't seem great; so possibly
we should add some kind of registration interface that also allows
extensions to specify a priority, so that we can print details in
a predictable order. However, that would be less similar to existing
hooks, and perhaps not worth the complexity, so do this for now.
---
 contrib/auto_explain/auto_explain.c  |  1 +
 contrib/file_fdw/file_fdw.c          |  1 +
 src/backend/commands/explain.c       | 13 +++++++++++++
 src/include/commands/explain.h       | 17 +++++++++++++++++
 src/include/commands/explain_state.h |  4 ++++
 5 files changed, 36 insertions(+)

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 2123877f1ac..3b73bd19107 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -15,6 +15,7 @@
 #include <limits.h>
 
 #include "access/parallel.h"
+#include "commands/explain.h"
 #include "commands/explain_format.h"
 #include "commands/explain_state.h"
 #include "common/pg_prng.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 05b01a305c1..56ececac70b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -27,6 +27,7 @@
 #include "commands/explain_format.h"
 #include "commands/explain_state.h"
 #include "commands/vacuum.h"
+#include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 7c203420fed..a3d40c9934f 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -51,6 +51,9 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* per-plan and per-node hooks for plugins to print additional info */
+explain_per_plan_hook_type explain_per_plan_hook = NULL;
+explain_per_node_hook_type explain_per_node_hook = NULL;
 
 /*
  * Various places within need to convert bytes to kilobytes.  Round these up
@@ -647,6 +650,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 	if (es->serialize != EXPLAIN_SERIALIZE_NONE)
 		ExplainPrintSerialize(es, &serializeMetrics);
 
+	/* Allow plugins to print additional information */
+	if (explain_per_plan_hook)
+		(*explain_per_plan_hook) (plannedstmt, into, es, queryString,
+								  params, queryEnv);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -2307,6 +2315,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		ExplainFlushWorkersState(es);
 	es->workers_state = save_workers_state;
 
+	/* Allow plugins to print additional information */
+	if (explain_per_node_hook)
+		(*explain_per_node_hook) (planstate, ancestors, relationship,
+								  plan_name, es);
+
 	/*
 	 * If partition pruning was done during executor initialization, the
 	 * number of child plans we'll display below will be less than the number
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 7a091c3c505..32883aa6398 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -30,6 +30,23 @@ typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   QueryEnvironment *queryEnv);
 extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 
+/* Hook for EXPLAIN plugins to print extra information for each plan */
+typedef void (*explain_per_plan_hook_type) (PlannedStmt *plannedstmt,
+											IntoClause *into,
+											ExplainState *es,
+											const char *queryString,
+											ParamListInfo params,
+											QueryEnvironment *queryEnv);
+extern PGDLLIMPORT explain_per_plan_hook_type explain_per_plan_hook;
+
+/* Hook for EXPLAIN plugins to print extra fields on individual plan nodes */
+typedef void (*explain_per_node_hook_type) (PlanState *planstate,
+											List *ancestors,
+											const char *relationship,
+											const char *plan_name,
+											ExplainState *es);
+extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
+
 /* Hook for plugins to get control in explain_get_index_name() */
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
index a753bd44c5e..694f4699605 100644
--- a/src/include/commands/explain_state.h
+++ b/src/include/commands/explain_state.h
@@ -13,6 +13,10 @@
 #ifndef EXPLAIN_STATE_H
 #define EXPLAIN_STATE_H
 
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+#include "parser/parse_node.h"
+
 struct ExplainState;
 typedef struct ExplainState ExplainState;
 
-- 
2.39.3 (Apple Git-145)

From 0ca91dbf9580aa1009662e1bf2b6bf2c7d86bfb2 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 12:07:26 -0500
Subject: [PATCH v2 3/3] pg_overexplain: Additional EXPLAIN options for
 debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1576 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..9c1247ed498
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e70c9368d94..838ea282326 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4246,3 +4246,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From caaa060916cedddfc14d32ecf98003abbf8a6d0d Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 20 Feb 2025 13:54:55 -0500
Subject: [PATCH v2 1/3] Make it possible for loadable modules to add EXPLAIN
 options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
---
 contrib/auto_explain/auto_explain.c   |   2 +-
 contrib/file_fdw/file_fdw.c           |   2 +-
 contrib/postgres_fdw/postgres_fdw.c   |   2 +-
 src/backend/commands/Makefile         |   1 +
 src/backend/commands/explain.c        | 142 +----------
 src/backend/commands/explain_dr.c     |   1 +
 src/backend/commands/explain_format.c |   1 +
 src/backend/commands/explain_state.c  | 351 ++++++++++++++++++++++++++
 src/backend/commands/meson.build      |   1 +
 src/backend/commands/prepare.c        |   1 +
 src/include/commands/explain.h        |  59 +----
 src/include/commands/explain_state.h  |  94 +++++++
 src/tools/pgindent/typedefs.list      |   2 +
 13 files changed, 461 insertions(+), 198 deletions(-)
 create mode 100644 src/backend/commands/explain_state.c
 create mode 100644 src/include/commands/explain_state.h

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 7007a226c08..2123877f1ac 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -15,8 +15,8 @@
 #include <limits.h>
 
 #include "access/parallel.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "utils/guc.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index bf707c812ed..05b01a305c1 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -24,8 +24,8 @@
 #include "commands/copy.h"
 #include "commands/copyfrom_internal.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/vacuum.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 1131a8bf77e..263c879026e 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -19,8 +19,8 @@
 #include "access/table.h"
 #include "catalog/pg_opfamily.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "executor/execAsync.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index 85cfea6fd71..cb2fbdc7c60 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -36,6 +36,7 @@ OBJS = \
 	explain.o \
 	explain_dr.o \
 	explain_format.o \
+	explain_state.o \
 	extension.o \
 	foreigncmds.o \
 	functioncmds.o \
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d8a7232cedb..7c203420fed 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -19,6 +19,7 @@
 #include "commands/defrem.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -170,130 +171,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -354,22 +236,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	pfree(es->str->data);
 }
 
-/*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
 /*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
diff --git a/src/backend/commands/explain_dr.c b/src/backend/commands/explain_dr.c
index fb42bee6e72..5715546cf43 100644
--- a/src/backend/commands/explain_dr.c
+++ b/src/backend/commands/explain_dr.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_dr.h"
+#include "commands/explain_state.h"
 #include "libpq/pqformat.h"
 #include "libpq/protocol.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/commands/explain_format.c b/src/backend/commands/explain_format.c
index bccdd76a874..752691d56db 100644
--- a/src/backend/commands/explain_format.c
+++ b/src/backend/commands/explain_format.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "utils/json.h"
 #include "utils/xml.h"
 
diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
new file mode 100644
index 00000000000..6235c95d4c5
--- /dev/null
+++ b/src/backend/commands/explain_state.c
@@ -0,0 +1,351 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.c
+ *	  Code for initializing and accessing ExplainState objects
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * In-core options have hard-coded fields inside ExplainState; e.g. if
+ * the user writes EXPLAIN (BUFFERS) then ExplainState's "buffers" member
+ * will be set to true. Extensions can also register options using
+ * RegisterExtensionExplainOption; so that e.g. EXPLAIN (BICYCLE 'red')
+ * will invoke a designated handler that knows what the legal values are
+ * for the BICYCLE option. However, it's not enough for an extension to be
+ * able to parse new options: it also needs a place to store the results
+ * of that parsing, and an ExplainState has no 'bicycle' field.
+ *
+ * To solve this problem, an ExplainState can contain an array of opaque
+ * pointers, one per extension. An extension can use GetExplainExtensionId
+ * to acquire an integer ID to acquire an offset into this array that is
+ * reserved for its exclusive use, and then use GetExplainExtensionState
+ * and SetExplainExtensionState to read and write its own private state
+ * within an ExplainState.
+ *
+ * Note that there is no requirement that the name of the option match
+ * the name of the extension; e.g. a pg_explain_conveyance extension could
+ * implement options for BICYCLE, MONORAIL, etc.
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/explain_state.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_state.h"
+
+typedef struct
+{
+	const char *option_name;
+	ExplainOptionHandler option_handler;
+} ExplainExtensionOption;
+
+static const char **ExplainExtensionNameArray = NULL;
+static int	ExplainExtensionNamesAssigned = 0;
+static int	ExplainExtensionNamesAllocated = 0;
+
+static ExplainExtensionOption *ExplainExtensionOptionArray = NULL;
+static int	ExplainExtensionOptionsAssigned = 0;
+static int	ExplainExtensionOptionsAllocated = 0;
+
+/*
+ * Create a new ExplainState struct initialized with default options.
+ */
+ExplainState *
+NewExplainState(void)
+{
+	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
+
+	/* Set default options (most fields can be left as zeroes). */
+	es->costs = true;
+	/* Prepare output buffer. */
+	es->str = makeStringInfo();
+
+	return es;
+}
+
+/*
+ * Parse a list of EXPLAIN options and update an ExplainState accordingly.
+ */
+void
+ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
+{
+	ListCell   *lc;
+	bool		timing_set = false;
+	bool		buffers_set = false;
+	bool		summary_set = false;
+
+	/* Parse options list. */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		if (strcmp(opt->defname, "analyze") == 0)
+			es->analyze = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "verbose") == 0)
+			es->verbose = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "costs") == 0)
+			es->costs = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "buffers") == 0)
+		{
+			buffers_set = true;
+			es->buffers = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "wal") == 0)
+			es->wal = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "settings") == 0)
+			es->settings = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "generic_plan") == 0)
+			es->generic = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "timing") == 0)
+		{
+			timing_set = true;
+			es->timing = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "summary") == 0)
+		{
+			summary_set = true;
+			es->summary = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "serialize") == 0)
+		{
+			if (opt->arg)
+			{
+				char	   *p = defGetString(opt);
+
+				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_NONE;
+				else if (strcmp(p, "text") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_TEXT;
+				else if (strcmp(p, "binary") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_BINARY;
+				else
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+									opt->defname, p),
+							 parser_errposition(pstate, opt->location)));
+			}
+			else
+			{
+				/* SERIALIZE without an argument is taken as 'text' */
+				es->serialize = EXPLAIN_SERIALIZE_TEXT;
+			}
+		}
+		else if (strcmp(opt->defname, "format") == 0)
+		{
+			char	   *p = defGetString(opt);
+
+			if (strcmp(p, "text") == 0)
+				es->format = EXPLAIN_FORMAT_TEXT;
+			else if (strcmp(p, "xml") == 0)
+				es->format = EXPLAIN_FORMAT_XML;
+			else if (strcmp(p, "json") == 0)
+				es->format = EXPLAIN_FORMAT_JSON;
+			else if (strcmp(p, "yaml") == 0)
+				es->format = EXPLAIN_FORMAT_YAML;
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+								opt->defname, p),
+						 parser_errposition(pstate, opt->location)));
+		}
+		else if (!ApplyExtensionExplainOption(es, opt, pstate))
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("unrecognized EXPLAIN option \"%s\"",
+							opt->defname),
+					 parser_errposition(pstate, opt->location)));
+	}
+
+	/* check that WAL is used with EXPLAIN ANALYZE */
+	if (es->wal && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
+
+	/* if the timing was not set explicitly, set default value */
+	es->timing = (timing_set) ? es->timing : es->analyze;
+
+	/* if the buffers was not set explicitly, set default value */
+	es->buffers = (buffers_set) ? es->buffers : es->analyze;
+
+	/* check that timing is used with EXPLAIN ANALYZE */
+	if (es->timing && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
+
+	/* check that serialize is used with EXPLAIN ANALYZE */
+	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
+
+	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
+	if (es->generic && es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
+
+	/* if the summary was not set explicitly, set default value */
+	es->summary = (summary_set) ? es->summary : es->analyze;
+}
+
+/*
+ * Map the name of an EXPLAIN extension to an integer ID.
+ *
+ * Within the lifetime of a particular backend, the same name will be mapped
+ * to the same ID every time. IDs are not stable across backends. Use the ID
+ * that you get from this function to call GetExplainExtensionState and
+ * SetExplainExtensionState.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+int
+GetExplainExtensionId(const char *extension_name)
+{
+	/* Search for an existing extension by this name; if found, return ID. */
+	for (int i = 0; i < ExplainExtensionNamesAssigned; ++i)
+		if (strcmp(ExplainExtensionNameArray[i], extension_name) == 0)
+			return i;
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionNameArray == NULL)
+	{
+		ExplainExtensionNamesAllocated = 16;
+		ExplainExtensionNameArray = (const char **)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionNamesAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionNamesAssigned >= ExplainExtensionNamesAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionNamesAssigned + 1);
+
+		ExplainExtensionNameArray = (const char **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(char *));
+		ExplainExtensionNamesAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	ExplainExtensionNameArray[ExplainExtensionNamesAssigned] = extension_name;
+	return ExplainExtensionNamesAssigned++;
+}
+
+/*
+ * Get extension-specific state from an ExplainState.
+ *
+ * See comments for SetExplainExtensionState, below.
+ */
+void *
+GetExplainExtensionState(ExplainState *es, int extension_id)
+{
+	if (extension_id >= es->extension_state_allocated)
+		return NULL;
+	return es->extension_state[extension_id];
+}
+
+/*
+ * Store extension-specific state into an ExplainState.
+ *
+ * To use this function, first obtain an integer extension_id using
+ * GetExplainExtensionId. Then use this function to store an opaque pointer
+ * in the ExplainState. Later, you can retrieve the opaque pointer using
+ * GetExplainExtensionState.
+ */
+void
+SetExplainExtensionState(ExplainState *es, int extension_id, void *opaque)
+{
+	if (extension_id >= es->extension_state_allocated)
+	{
+		int			i;
+
+		i = Max(16, pg_nextpower2_32(es->extension_state_allocated + 1));
+		es->extension_state = (void **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(void *));
+		es->extension_state_allocated = i;
+	}
+
+	es->extension_state[extension_id] = opaque;
+}
+
+/*
+ * Register a new EXPLAIN option.
+ *
+ * When option_name is used as an EXPLAIN option, handler will be called and
+ * should update the ExplainState passed to it. See comments at top of file
+ * for a more detailed explanation.
+ */
+void
+RegisterExtensionExplainOption(char *option_name, ExplainOptionHandler handler)
+{
+	ExplainExtensionOption *exopt;
+
+	/* Search for an existing option by this name; if found, update handler. */
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   option_name) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler = handler;
+			return;
+		}
+	}
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionOptionArray == NULL)
+	{
+		ExplainExtensionOptionsAllocated = 16;
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionOptionsAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionOptionsAssigned >= ExplainExtensionOptionsAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionOptionsAssigned + 1);
+
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			repalloc(ExplainExtensionOptionArray, i * sizeof(char *));
+		ExplainExtensionOptionsAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	exopt = &ExplainExtensionOptionArray[ExplainExtensionOptionsAssigned++];
+	exopt->option_name = option_name;
+	exopt->option_handler = handler;
+}
+
+/*
+ * Apply an EXPLAIN option registered by an extension.
+ *
+ * If no extension has registered the named option, returns false. Otherwise,
+ * calls the appropriate handler function and then returns true.
+ */
+bool
+ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index ce8d1ab8bac..dd4cde41d32 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -24,6 +24,7 @@ backend_sources += files(
   'explain.c',
   'explain_dr.c',
   'explain_format.c',
+  'explain_state.c',
   'extension.c',
   'foreigncmds.c',
   'functioncmds.c',
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 4d68d4d25c7..be92627bc8c 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "funcapi.h"
 #include "nodes/nodeFuncs.h"
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 64547bd9b9c..7a091c3c505 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -17,61 +17,8 @@
 #include "lib/stringinfo.h"
 #include "parser/parse_node.h"
 
-typedef enum ExplainSerializeOption
-{
-	EXPLAIN_SERIALIZE_NONE,
-	EXPLAIN_SERIALIZE_TEXT,
-	EXPLAIN_SERIALIZE_BINARY,
-} ExplainSerializeOption;
-
-typedef enum ExplainFormat
-{
-	EXPLAIN_FORMAT_TEXT,
-	EXPLAIN_FORMAT_XML,
-	EXPLAIN_FORMAT_JSON,
-	EXPLAIN_FORMAT_YAML,
-} ExplainFormat;
-
-typedef struct ExplainWorkersState
-{
-	int			num_workers;	/* # of worker processes the plan used */
-	bool	   *worker_inited;	/* per-worker state-initialized flags */
-	StringInfoData *worker_str; /* per-worker transient output buffers */
-	int		   *worker_state_save;	/* per-worker grouping state save areas */
-	StringInfo	prev_str;		/* saved output buffer while redirecting */
-} ExplainWorkersState;
-
-typedef struct ExplainState
-{
-	StringInfo	str;			/* output buffer */
-	/* options */
-	bool		verbose;		/* be verbose */
-	bool		analyze;		/* print actual times */
-	bool		costs;			/* print estimated costs */
-	bool		buffers;		/* print buffer usage */
-	bool		wal;			/* print WAL usage */
-	bool		timing;			/* print detailed node timing */
-	bool		summary;		/* print total planning and execution timing */
-	bool		memory;			/* print planner's memory usage information */
-	bool		settings;		/* print modified settings */
-	bool		generic;		/* generate a generic plan */
-	ExplainSerializeOption serialize;	/* serialize the query's output? */
-	ExplainFormat format;		/* output format */
-	/* state for output formatting --- not reset for each new plan tree */
-	int			indent;			/* current indentation level */
-	List	   *grouping_stack; /* format-specific grouping state */
-	/* state related to the current plan tree (filled by ExplainPrintPlan) */
-	PlannedStmt *pstmt;			/* top of plan */
-	List	   *rtable;			/* range table */
-	List	   *rtable_names;	/* alias names for RTEs */
-	List	   *deparse_cxt;	/* context list for deparsing expressions */
-	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
-	bool		hide_workers;	/* set if we find an invisible Gather */
-	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
-								 * entry */
-	/* state related to the current plan node */
-	ExplainWorkersState *workers_state; /* needed if parallel plan */
-} ExplainState;
+struct ExplainState;
+typedef struct ExplainState ExplainState;
 
 /* Hook for plugins to get control in ExplainOneQuery() */
 typedef void (*ExplainOneQuery_hook_type) (Query *query,
@@ -95,8 +42,6 @@ extern void standard_ExplainOneQuery(Query *query, int cursorOptions,
 									 const char *queryString, ParamListInfo params,
 									 QueryEnvironment *queryEnv);
 
-extern ExplainState *NewExplainState(void);
-
 extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
 
 extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
new file mode 100644
index 00000000000..a753bd44c5e
--- /dev/null
+++ b/src/include/commands/explain_state.h
@@ -0,0 +1,94 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.h
+ *	  prototypes for explain_state.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * src/include/commands/explain_state.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXPLAIN_STATE_H
+#define EXPLAIN_STATE_H
+
+struct ExplainState;
+typedef struct ExplainState ExplainState;
+
+typedef enum ExplainSerializeOption
+{
+	EXPLAIN_SERIALIZE_NONE,
+	EXPLAIN_SERIALIZE_TEXT,
+	EXPLAIN_SERIALIZE_BINARY,
+} ExplainSerializeOption;
+
+typedef enum ExplainFormat
+{
+	EXPLAIN_FORMAT_TEXT,
+	EXPLAIN_FORMAT_XML,
+	EXPLAIN_FORMAT_JSON,
+	EXPLAIN_FORMAT_YAML,
+} ExplainFormat;
+
+typedef struct ExplainWorkersState
+{
+	int			num_workers;	/* # of worker processes the plan used */
+	bool	   *worker_inited;	/* per-worker state-initialized flags */
+	StringInfoData *worker_str; /* per-worker transient output buffers */
+	int		   *worker_state_save;	/* per-worker grouping state save areas */
+	StringInfo	prev_str;		/* saved output buffer while redirecting */
+} ExplainWorkersState;
+
+struct ExplainState
+{
+	StringInfo	str;			/* output buffer */
+	/* options */
+	bool		verbose;		/* be verbose */
+	bool		analyze;		/* print actual times */
+	bool		costs;			/* print estimated costs */
+	bool		buffers;		/* print buffer usage */
+	bool		wal;			/* print WAL usage */
+	bool		timing;			/* print detailed node timing */
+	bool		summary;		/* print total planning and execution timing */
+	bool		memory;			/* print planner's memory usage information */
+	bool		settings;		/* print modified settings */
+	bool		generic;		/* generate a generic plan */
+	ExplainSerializeOption serialize;	/* serialize the query's output? */
+	ExplainFormat format;		/* output format */
+	/* state for output formatting --- not reset for each new plan tree */
+	int			indent;			/* current indentation level */
+	List	   *grouping_stack; /* format-specific grouping state */
+	/* state related to the current plan tree (filled by ExplainPrintPlan) */
+	PlannedStmt *pstmt;			/* top of plan */
+	List	   *rtable;			/* range table */
+	List	   *rtable_names;	/* alias names for RTEs */
+	List	   *deparse_cxt;	/* context list for deparsing expressions */
+	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
+	bool		hide_workers;	/* set if we find an invisible Gather */
+	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
+								 * entry */
+	/* state related to the current plan node */
+	ExplainWorkersState *workers_state; /* needed if parallel plan */
+	/* extensions */
+	void	  **extension_state;
+	int			extension_state_allocated;
+};
+
+typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+
+extern ExplainState *NewExplainState(void);
+extern void ParseExplainOptionList(ExplainState *es, List *options,
+								   ParseState *pstate);
+
+extern int	GetExplainExtensionId(const char *extension_name);
+extern void *GetExplainExtensionState(ExplainState *es, int extension_id);
+extern void SetExplainExtensionState(ExplainState *es, int extension_id,
+									 void *opaque);
+
+extern void RegisterExtensionExplainOption(char *option_name,
+										   ExplainOptionHandler handler);
+extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
+										ParseState *pstate);
+
+#endif							/* EXPLAIN_STATE_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9840060997f..e70c9368d94 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4244,3 +4244,5 @@ yyscan_t
 z_stream
 z_streamp
 zic_t
+ExplainExtensionOption
+ExplainOptionHandler
-- 
2.39.3 (Apple Git-145)

From d0bce2d566a1cb3185f42b43679ba4eb53de6550 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 14:50:52 -0500
Subject: [PATCH v3 2/3] Add some new hooks so extensions can add details to
 EXPLAIN.

Specifically, add a per-node hook that is called after the per-node
information has been displayed but before we display children, and a
per-query hook that is called after existing query-level information
is printed. This assumes that extension-added information should
always go at the end rather than the beginning or the middle, but
that seems like an acceptable limitation for simplicity. It also
assumes that extensions will only want to add information, not remove
or reformat existing details; those also seem like acceptable
restrictions, at least for now.

If multiple EXPLAIN extensions are used, the order in which any
additional details are printed is likely to depend on the order in
which the modules are loaded. That doesn't seem great; so possibly
we should add some kind of registration interface that also allows
extensions to specify a priority, so that we can print details in
a predictable order. However, that would be less similar to existing
hooks, and perhaps not worth the complexity, so do this for now.
---
 src/backend/commands/explain.c | 13 +++++++++++++
 src/include/commands/explain.h | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 7c203420fed..a3d40c9934f 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -51,6 +51,9 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* per-plan and per-node hooks for plugins to print additional info */
+explain_per_plan_hook_type explain_per_plan_hook = NULL;
+explain_per_node_hook_type explain_per_node_hook = NULL;
 
 /*
  * Various places within need to convert bytes to kilobytes.  Round these up
@@ -647,6 +650,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 	if (es->serialize != EXPLAIN_SERIALIZE_NONE)
 		ExplainPrintSerialize(es, &serializeMetrics);
 
+	/* Allow plugins to print additional information */
+	if (explain_per_plan_hook)
+		(*explain_per_plan_hook) (plannedstmt, into, es, queryString,
+								  params, queryEnv);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -2307,6 +2315,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		ExplainFlushWorkersState(es);
 	es->workers_state = save_workers_state;
 
+	/* Allow plugins to print additional information */
+	if (explain_per_node_hook)
+		(*explain_per_node_hook) (planstate, ancestors, relationship,
+								  plan_name, es);
+
 	/*
 	 * If partition pruning was done during executor initialization, the
 	 * number of child plans we'll display below will be less than the number
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index f430142a946..1e8cc180058 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -29,6 +29,23 @@ typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   QueryEnvironment *queryEnv);
 extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 
+/* Hook for EXPLAIN plugins to print extra information for each plan */
+typedef void (*explain_per_plan_hook_type) (PlannedStmt *plannedstmt,
+											IntoClause *into,
+											ExplainState *es,
+											const char *queryString,
+											ParamListInfo params,
+											QueryEnvironment *queryEnv);
+extern PGDLLIMPORT explain_per_plan_hook_type explain_per_plan_hook;
+
+/* Hook for EXPLAIN plugins to print extra fields on individual plan nodes */
+typedef void (*explain_per_node_hook_type) (PlanState *planstate,
+											List *ancestors,
+											const char *relationship,
+											const char *plan_name,
+											ExplainState *es);
+extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
+
 /* Hook for plugins to get control in explain_get_index_name() */
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
-- 
2.39.3 (Apple Git-145)

From c3f69a223d9cbfc60a7ac279a102c228338ea485 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 14:49:23 -0500
Subject: [PATCH v3 1/3] Make it possible for loadable modules to add EXPLAIN
 options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
---
 contrib/auto_explain/auto_explain.c   |   1 +
 contrib/file_fdw/file_fdw.c           |   3 +-
 contrib/postgres_fdw/postgres_fdw.c   |   2 +-
 src/backend/commands/Makefile         |   1 +
 src/backend/commands/explain.c        | 142 +---------
 src/backend/commands/explain_dr.c     |   1 +
 src/backend/commands/explain_format.c |   1 +
 src/backend/commands/explain_state.c  | 369 ++++++++++++++++++++++++++
 src/backend/commands/meson.build      |   1 +
 src/backend/commands/prepare.c        |   1 +
 src/include/commands/explain.h        |  58 +---
 src/include/commands/explain_state.h  |  95 +++++++
 src/tools/pgindent/typedefs.list      |   2 +
 13 files changed, 480 insertions(+), 197 deletions(-)
 create mode 100644 src/backend/commands/explain_state.c
 create mode 100644 src/include/commands/explain_state.h

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 7007a226c08..3b73bd19107 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -17,6 +17,7 @@
 #include "access/parallel.h"
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "utils/guc.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index bf707c812ed..56ececac70b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -24,9 +24,10 @@
 #include "commands/copy.h"
 #include "commands/copyfrom_internal.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/vacuum.h"
+#include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 1131a8bf77e..263c879026e 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -19,8 +19,8 @@
 #include "access/table.h"
 #include "catalog/pg_opfamily.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "executor/execAsync.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index 85cfea6fd71..cb2fbdc7c60 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -36,6 +36,7 @@ OBJS = \
 	explain.o \
 	explain_dr.o \
 	explain_format.o \
+	explain_state.o \
 	extension.o \
 	foreigncmds.o \
 	functioncmds.o \
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d8a7232cedb..7c203420fed 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -19,6 +19,7 @@
 #include "commands/defrem.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -170,130 +171,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -354,22 +236,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	pfree(es->str->data);
 }
 
-/*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
 /*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
diff --git a/src/backend/commands/explain_dr.c b/src/backend/commands/explain_dr.c
index fb42bee6e72..5715546cf43 100644
--- a/src/backend/commands/explain_dr.c
+++ b/src/backend/commands/explain_dr.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_dr.h"
+#include "commands/explain_state.h"
 #include "libpq/pqformat.h"
 #include "libpq/protocol.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/commands/explain_format.c b/src/backend/commands/explain_format.c
index bccdd76a874..752691d56db 100644
--- a/src/backend/commands/explain_format.c
+++ b/src/backend/commands/explain_format.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "utils/json.h"
 #include "utils/xml.h"
 
diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
new file mode 100644
index 00000000000..f4cd6138da3
--- /dev/null
+++ b/src/backend/commands/explain_state.c
@@ -0,0 +1,369 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.c
+ *	  Code for initializing and accessing ExplainState objects
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * In-core options have hard-coded fields inside ExplainState; e.g. if
+ * the user writes EXPLAIN (BUFFERS) then ExplainState's "buffers" member
+ * will be set to true. Extensions can also register options using
+ * RegisterExtensionExplainOption; so that e.g. EXPLAIN (BICYCLE 'red')
+ * will invoke a designated handler that knows what the legal values are
+ * for the BICYCLE option. However, it's not enough for an extension to be
+ * able to parse new options: it also needs a place to store the results
+ * of that parsing, and an ExplainState has no 'bicycle' field.
+ *
+ * To solve this problem, an ExplainState can contain an array of opaque
+ * pointers, one per extension. An extension can use GetExplainExtensionId
+ * to acquire an integer ID to acquire an offset into this array that is
+ * reserved for its exclusive use, and then use GetExplainExtensionState
+ * and SetExplainExtensionState to read and write its own private state
+ * within an ExplainState.
+ *
+ * Note that there is no requirement that the name of the option match
+ * the name of the extension; e.g. a pg_explain_conveyance extension could
+ * implement options for BICYCLE, MONORAIL, etc.
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/explain_state.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_state.h"
+
+typedef struct
+{
+	const char *option_name;
+	ExplainOptionHandler option_handler;
+} ExplainExtensionOption;
+
+static const char **ExplainExtensionNameArray = NULL;
+static int	ExplainExtensionNamesAssigned = 0;
+static int	ExplainExtensionNamesAllocated = 0;
+
+static ExplainExtensionOption *ExplainExtensionOptionArray = NULL;
+static int	ExplainExtensionOptionsAssigned = 0;
+static int	ExplainExtensionOptionsAllocated = 0;
+
+/*
+ * Create a new ExplainState struct initialized with default options.
+ */
+ExplainState *
+NewExplainState(void)
+{
+	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
+
+	/* Set default options (most fields can be left as zeroes). */
+	es->costs = true;
+	/* Prepare output buffer. */
+	es->str = makeStringInfo();
+
+	return es;
+}
+
+/*
+ * Parse a list of EXPLAIN options and update an ExplainState accordingly.
+ */
+void
+ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
+{
+	ListCell   *lc;
+	bool		timing_set = false;
+	bool		buffers_set = false;
+	bool		summary_set = false;
+
+	/* Parse options list. */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		if (strcmp(opt->defname, "analyze") == 0)
+			es->analyze = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "verbose") == 0)
+			es->verbose = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "costs") == 0)
+			es->costs = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "buffers") == 0)
+		{
+			buffers_set = true;
+			es->buffers = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "wal") == 0)
+			es->wal = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "settings") == 0)
+			es->settings = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "generic_plan") == 0)
+			es->generic = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "timing") == 0)
+		{
+			timing_set = true;
+			es->timing = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "summary") == 0)
+		{
+			summary_set = true;
+			es->summary = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "serialize") == 0)
+		{
+			if (opt->arg)
+			{
+				char	   *p = defGetString(opt);
+
+				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_NONE;
+				else if (strcmp(p, "text") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_TEXT;
+				else if (strcmp(p, "binary") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_BINARY;
+				else
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+									opt->defname, p),
+							 parser_errposition(pstate, opt->location)));
+			}
+			else
+			{
+				/* SERIALIZE without an argument is taken as 'text' */
+				es->serialize = EXPLAIN_SERIALIZE_TEXT;
+			}
+		}
+		else if (strcmp(opt->defname, "format") == 0)
+		{
+			char	   *p = defGetString(opt);
+
+			if (strcmp(p, "text") == 0)
+				es->format = EXPLAIN_FORMAT_TEXT;
+			else if (strcmp(p, "xml") == 0)
+				es->format = EXPLAIN_FORMAT_XML;
+			else if (strcmp(p, "json") == 0)
+				es->format = EXPLAIN_FORMAT_JSON;
+			else if (strcmp(p, "yaml") == 0)
+				es->format = EXPLAIN_FORMAT_YAML;
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+								opt->defname, p),
+						 parser_errposition(pstate, opt->location)));
+		}
+		else if (!ApplyExtensionExplainOption(es, opt, pstate))
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("unrecognized EXPLAIN option \"%s\"",
+							opt->defname),
+					 parser_errposition(pstate, opt->location)));
+	}
+
+	/* check that WAL is used with EXPLAIN ANALYZE */
+	if (es->wal && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
+
+	/* if the timing was not set explicitly, set default value */
+	es->timing = (timing_set) ? es->timing : es->analyze;
+
+	/* if the buffers was not set explicitly, set default value */
+	es->buffers = (buffers_set) ? es->buffers : es->analyze;
+
+	/* check that timing is used with EXPLAIN ANALYZE */
+	if (es->timing && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
+
+	/* check that serialize is used with EXPLAIN ANALYZE */
+	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
+
+	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
+	if (es->generic && es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
+
+	/* if the summary was not set explicitly, set default value */
+	es->summary = (summary_set) ? es->summary : es->analyze;
+}
+
+/*
+ * Map the name of an EXPLAIN extension to an integer ID.
+ *
+ * Within the lifetime of a particular backend, the same name will be mapped
+ * to the same ID every time. IDs are not stable across backends. Use the ID
+ * that you get from this function to call GetExplainExtensionState and
+ * SetExplainExtensionState.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+int
+GetExplainExtensionId(const char *extension_name)
+{
+	/* Search for an existing extension by this name; if found, return ID. */
+	for (int i = 0; i < ExplainExtensionNamesAssigned; ++i)
+		if (strcmp(ExplainExtensionNameArray[i], extension_name) == 0)
+			return i;
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionNameArray == NULL)
+	{
+		ExplainExtensionNamesAllocated = 16;
+		ExplainExtensionNameArray = (const char **)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionNamesAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionNamesAssigned >= ExplainExtensionNamesAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionNamesAssigned + 1);
+
+		ExplainExtensionNameArray = (const char **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(char *));
+		ExplainExtensionNamesAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	ExplainExtensionNameArray[ExplainExtensionNamesAssigned] = extension_name;
+	return ExplainExtensionNamesAssigned++;
+}
+
+/*
+ * Get extension-specific state from an ExplainState.
+ *
+ * See comments for SetExplainExtensionState, below.
+ */
+void *
+GetExplainExtensionState(ExplainState *es, int extension_id)
+{
+	Assert(extension_id >= 0);
+
+	if (extension_id >= es->extension_state_allocated)
+		return NULL;
+
+	return es->extension_state[extension_id];
+}
+
+/*
+ * Store extension-specific state into an ExplainState.
+ *
+ * To use this function, first obtain an integer extension_id using
+ * GetExplainExtensionId. Then use this function to store an opaque pointer
+ * in the ExplainState. Later, you can retrieve the opaque pointer using
+ * GetExplainExtensionState.
+ */
+void
+SetExplainExtensionState(ExplainState *es, int extension_id, void *opaque)
+{
+	Assert(extension_id >= 0);
+
+	/* If there is no array yet, create one. */
+	if (es->extension_state == NULL)
+	{
+		es->extension_state_allocated = 16;
+		es->extension_state =
+			palloc0(es->extension_state_allocated * sizeof(void *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (extension_id >= es->extension_state_allocated)
+	{
+		int			i;
+
+		i = pg_nextpower2_32(es->extension_state_allocated + 1);
+		es->extension_state = (void **)
+			repalloc(es->extension_state, i * sizeof(void *));
+		es->extension_state_allocated = i;
+	}
+
+	es->extension_state[extension_id] = opaque;
+}
+
+/*
+ * Register a new EXPLAIN option.
+ *
+ * When option_name is used as an EXPLAIN option, handler will be called and
+ * should update the ExplainState passed to it. See comments at top of file
+ * for a more detailed explanation.
+ *
+ * option_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+void
+RegisterExtensionExplainOption(const char *option_name,
+							   ExplainOptionHandler handler)
+{
+	ExplainExtensionOption *exopt;
+
+	/* Search for an existing option by this name; if found, update handler. */
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   option_name) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler = handler;
+			return;
+		}
+	}
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionOptionArray == NULL)
+	{
+		ExplainExtensionOptionsAllocated = 16;
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionOptionsAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionOptionsAssigned >= ExplainExtensionOptionsAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionOptionsAssigned + 1);
+
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			repalloc(ExplainExtensionOptionArray, i * sizeof(char *));
+		ExplainExtensionOptionsAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	exopt = &ExplainExtensionOptionArray[ExplainExtensionOptionsAssigned++];
+	exopt->option_name = option_name;
+	exopt->option_handler = handler;
+}
+
+/*
+ * Apply an EXPLAIN option registered by an extension.
+ *
+ * If no extension has registered the named option, returns false. Otherwise,
+ * calls the appropriate handler function and then returns true.
+ */
+bool
+ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index ce8d1ab8bac..dd4cde41d32 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -24,6 +24,7 @@ backend_sources += files(
   'explain.c',
   'explain_dr.c',
   'explain_format.c',
+  'explain_state.c',
   'extension.c',
   'foreigncmds.c',
   'functioncmds.c',
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 4d68d4d25c7..be92627bc8c 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "funcapi.h"
 #include "nodes/nodeFuncs.h"
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 64547bd9b9c..f430142a946 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -17,61 +17,7 @@
 #include "lib/stringinfo.h"
 #include "parser/parse_node.h"
 
-typedef enum ExplainSerializeOption
-{
-	EXPLAIN_SERIALIZE_NONE,
-	EXPLAIN_SERIALIZE_TEXT,
-	EXPLAIN_SERIALIZE_BINARY,
-} ExplainSerializeOption;
-
-typedef enum ExplainFormat
-{
-	EXPLAIN_FORMAT_TEXT,
-	EXPLAIN_FORMAT_XML,
-	EXPLAIN_FORMAT_JSON,
-	EXPLAIN_FORMAT_YAML,
-} ExplainFormat;
-
-typedef struct ExplainWorkersState
-{
-	int			num_workers;	/* # of worker processes the plan used */
-	bool	   *worker_inited;	/* per-worker state-initialized flags */
-	StringInfoData *worker_str; /* per-worker transient output buffers */
-	int		   *worker_state_save;	/* per-worker grouping state save areas */
-	StringInfo	prev_str;		/* saved output buffer while redirecting */
-} ExplainWorkersState;
-
-typedef struct ExplainState
-{
-	StringInfo	str;			/* output buffer */
-	/* options */
-	bool		verbose;		/* be verbose */
-	bool		analyze;		/* print actual times */
-	bool		costs;			/* print estimated costs */
-	bool		buffers;		/* print buffer usage */
-	bool		wal;			/* print WAL usage */
-	bool		timing;			/* print detailed node timing */
-	bool		summary;		/* print total planning and execution timing */
-	bool		memory;			/* print planner's memory usage information */
-	bool		settings;		/* print modified settings */
-	bool		generic;		/* generate a generic plan */
-	ExplainSerializeOption serialize;	/* serialize the query's output? */
-	ExplainFormat format;		/* output format */
-	/* state for output formatting --- not reset for each new plan tree */
-	int			indent;			/* current indentation level */
-	List	   *grouping_stack; /* format-specific grouping state */
-	/* state related to the current plan tree (filled by ExplainPrintPlan) */
-	PlannedStmt *pstmt;			/* top of plan */
-	List	   *rtable;			/* range table */
-	List	   *rtable_names;	/* alias names for RTEs */
-	List	   *deparse_cxt;	/* context list for deparsing expressions */
-	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
-	bool		hide_workers;	/* set if we find an invisible Gather */
-	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
-								 * entry */
-	/* state related to the current plan node */
-	ExplainWorkersState *workers_state; /* needed if parallel plan */
-} ExplainState;
+typedef struct ExplainState ExplainState;	/* defined in explain_state.h */
 
 /* Hook for plugins to get control in ExplainOneQuery() */
 typedef void (*ExplainOneQuery_hook_type) (Query *query,
@@ -95,8 +41,6 @@ extern void standard_ExplainOneQuery(Query *query, int cursorOptions,
 									 const char *queryString, ParamListInfo params,
 									 QueryEnvironment *queryEnv);
 
-extern ExplainState *NewExplainState(void);
-
 extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
 
 extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
new file mode 100644
index 00000000000..925097492b9
--- /dev/null
+++ b/src/include/commands/explain_state.h
@@ -0,0 +1,95 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.h
+ *	  prototypes for explain_state.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * src/include/commands/explain_state.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXPLAIN_STATE_H
+#define EXPLAIN_STATE_H
+
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+#include "parser/parse_node.h"
+
+typedef enum ExplainSerializeOption
+{
+	EXPLAIN_SERIALIZE_NONE,
+	EXPLAIN_SERIALIZE_TEXT,
+	EXPLAIN_SERIALIZE_BINARY,
+} ExplainSerializeOption;
+
+typedef enum ExplainFormat
+{
+	EXPLAIN_FORMAT_TEXT,
+	EXPLAIN_FORMAT_XML,
+	EXPLAIN_FORMAT_JSON,
+	EXPLAIN_FORMAT_YAML,
+} ExplainFormat;
+
+typedef struct ExplainWorkersState
+{
+	int			num_workers;	/* # of worker processes the plan used */
+	bool	   *worker_inited;	/* per-worker state-initialized flags */
+	StringInfoData *worker_str; /* per-worker transient output buffers */
+	int		   *worker_state_save;	/* per-worker grouping state save areas */
+	StringInfo	prev_str;		/* saved output buffer while redirecting */
+} ExplainWorkersState;
+
+typedef struct ExplainState
+{
+	StringInfo	str;			/* output buffer */
+	/* options */
+	bool		verbose;		/* be verbose */
+	bool		analyze;		/* print actual times */
+	bool		costs;			/* print estimated costs */
+	bool		buffers;		/* print buffer usage */
+	bool		wal;			/* print WAL usage */
+	bool		timing;			/* print detailed node timing */
+	bool		summary;		/* print total planning and execution timing */
+	bool		memory;			/* print planner's memory usage information */
+	bool		settings;		/* print modified settings */
+	bool		generic;		/* generate a generic plan */
+	ExplainSerializeOption serialize;	/* serialize the query's output? */
+	ExplainFormat format;		/* output format */
+	/* state for output formatting --- not reset for each new plan tree */
+	int			indent;			/* current indentation level */
+	List	   *grouping_stack; /* format-specific grouping state */
+	/* state related to the current plan tree (filled by ExplainPrintPlan) */
+	PlannedStmt *pstmt;			/* top of plan */
+	List	   *rtable;			/* range table */
+	List	   *rtable_names;	/* alias names for RTEs */
+	List	   *deparse_cxt;	/* context list for deparsing expressions */
+	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
+	bool		hide_workers;	/* set if we find an invisible Gather */
+	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
+								 * entry */
+	/* state related to the current plan node */
+	ExplainWorkersState *workers_state; /* needed if parallel plan */
+	/* extensions */
+	void	  **extension_state;
+	int			extension_state_allocated;
+} ExplainState;
+
+typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+
+extern ExplainState *NewExplainState(void);
+extern void ParseExplainOptionList(ExplainState *es, List *options,
+								   ParseState *pstate);
+
+extern int	GetExplainExtensionId(const char *extension_name);
+extern void *GetExplainExtensionState(ExplainState *es, int extension_id);
+extern void SetExplainExtensionState(ExplainState *es, int extension_id,
+									 void *opaque);
+
+extern void RegisterExtensionExplainOption(const char *option_name,
+										   ExplainOptionHandler handler);
+extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
+										ParseState *pstate);
+
+#endif							/* EXPLAIN_STATE_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9840060997f..e70c9368d94 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4244,3 +4244,5 @@ yyscan_t
 z_stream
 z_streamp
 zic_t
+ExplainExtensionOption
+ExplainOptionHandler
-- 
2.39.3 (Apple Git-145)

From 2ccc0acc72c637c7fe73b12673ec92fc021c4d48 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 14:51:07 -0500
Subject: [PATCH v3 3/3] pg_overexplain: Additional EXPLAIN options for
 debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1576 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..9c1247ed498
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e70c9368d94..838ea282326 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4246,3 +4246,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 439f76c208fd38e98fb742990dd445af483b5010 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:06:07 -0500
Subject: [PATCH v4 2/3] Add some new hooks so extensions can add details to
 EXPLAIN.

Specifically, add a per-node hook that is called after the per-node
information has been displayed but before we display children, and a
per-query hook that is called after existing query-level information
is printed. This assumes that extension-added information should
always go at the end rather than the beginning or the middle, but
that seems like an acceptable limitation for simplicity. It also
assumes that extensions will only want to add information, not remove
or reformat existing details; those also seem like acceptable
restrictions, at least for now.

If multiple EXPLAIN extensions are used, the order in which any
additional details are printed is likely to depend on the order in
which the modules are loaded. That doesn't seem great; so possibly
we should add some kind of registration interface that also allows
extensions to specify a priority, so that we can print details in
a predictable order. However, that would be less similar to existing
hooks, and perhaps not worth the complexity, so do this for now.
---
 src/backend/commands/explain.c | 13 +++++++++++++
 src/include/commands/explain.h | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 7c203420fed..a3d40c9934f 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -51,6 +51,9 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* per-plan and per-node hooks for plugins to print additional info */
+explain_per_plan_hook_type explain_per_plan_hook = NULL;
+explain_per_node_hook_type explain_per_node_hook = NULL;
 
 /*
  * Various places within need to convert bytes to kilobytes.  Round these up
@@ -647,6 +650,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 	if (es->serialize != EXPLAIN_SERIALIZE_NONE)
 		ExplainPrintSerialize(es, &serializeMetrics);
 
+	/* Allow plugins to print additional information */
+	if (explain_per_plan_hook)
+		(*explain_per_plan_hook) (plannedstmt, into, es, queryString,
+								  params, queryEnv);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -2307,6 +2315,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		ExplainFlushWorkersState(es);
 	es->workers_state = save_workers_state;
 
+	/* Allow plugins to print additional information */
+	if (explain_per_node_hook)
+		(*explain_per_node_hook) (planstate, ancestors, relationship,
+								  plan_name, es);
+
 	/*
 	 * If partition pruning was done during executor initialization, the
 	 * number of child plans we'll display below will be less than the number
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 0ea313475f6..3ba7d16239f 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -28,6 +28,23 @@ typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   QueryEnvironment *queryEnv);
 extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 
+/* Hook for EXPLAIN plugins to print extra information for each plan */
+typedef void (*explain_per_plan_hook_type) (PlannedStmt *plannedstmt,
+											IntoClause *into,
+											ExplainState *es,
+											const char *queryString,
+											ParamListInfo params,
+											QueryEnvironment *queryEnv);
+extern PGDLLIMPORT explain_per_plan_hook_type explain_per_plan_hook;
+
+/* Hook for EXPLAIN plugins to print extra fields on individual plan nodes */
+typedef void (*explain_per_node_hook_type) (PlanState *planstate,
+											List *ancestors,
+											const char *relationship,
+											const char *plan_name,
+											ExplainState *es);
+extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
+
 /* Hook for plugins to get control in explain_get_index_name() */
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
-- 
2.39.3 (Apple Git-145)

From 2fa2523cf34ec40b5408aa4e4e1e167114a74b4d Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:08:07 -0500
Subject: [PATCH v4 3/3] pg_overexplain: Additional EXPLAIN options for
 debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1576 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..b83a9542a6b
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e70c9368d94..838ea282326 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4246,3 +4246,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 95c068a3340d9e3ef75b6948438b433ee37d507c Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:05:53 -0500
Subject: [PATCH v4 1/3] Make it possible for loadable modules to add EXPLAIN
 options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
---
 contrib/auto_explain/auto_explain.c   |   1 +
 contrib/file_fdw/file_fdw.c           |   3 +-
 contrib/postgres_fdw/postgres_fdw.c   |   2 +-
 src/backend/commands/Makefile         |   1 +
 src/backend/commands/explain.c        | 142 +---------
 src/backend/commands/explain_dr.c     |   1 +
 src/backend/commands/explain_format.c |   1 +
 src/backend/commands/explain_state.c  | 369 ++++++++++++++++++++++++++
 src/backend/commands/meson.build      |   1 +
 src/backend/commands/prepare.c        |   1 +
 src/include/commands/explain.h        |  59 +---
 src/include/commands/explain_state.h  |  95 +++++++
 src/tools/pgindent/typedefs.list      |   2 +
 13 files changed, 480 insertions(+), 198 deletions(-)
 create mode 100644 src/backend/commands/explain_state.c
 create mode 100644 src/include/commands/explain_state.h

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 7007a226c08..3b73bd19107 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -17,6 +17,7 @@
 #include "access/parallel.h"
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "utils/guc.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index bf707c812ed..56ececac70b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -24,9 +24,10 @@
 #include "commands/copy.h"
 #include "commands/copyfrom_internal.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/vacuum.h"
+#include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 1131a8bf77e..263c879026e 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -19,8 +19,8 @@
 #include "access/table.h"
 #include "catalog/pg_opfamily.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "executor/execAsync.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index 85cfea6fd71..cb2fbdc7c60 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -36,6 +36,7 @@ OBJS = \
 	explain.o \
 	explain_dr.o \
 	explain_format.o \
+	explain_state.o \
 	extension.o \
 	foreigncmds.o \
 	functioncmds.o \
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d8a7232cedb..7c203420fed 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -19,6 +19,7 @@
 #include "commands/defrem.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -170,130 +171,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -354,22 +236,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	pfree(es->str->data);
 }
 
-/*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
 /*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
diff --git a/src/backend/commands/explain_dr.c b/src/backend/commands/explain_dr.c
index fb42bee6e72..5715546cf43 100644
--- a/src/backend/commands/explain_dr.c
+++ b/src/backend/commands/explain_dr.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_dr.h"
+#include "commands/explain_state.h"
 #include "libpq/pqformat.h"
 #include "libpq/protocol.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/commands/explain_format.c b/src/backend/commands/explain_format.c
index bccdd76a874..752691d56db 100644
--- a/src/backend/commands/explain_format.c
+++ b/src/backend/commands/explain_format.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "utils/json.h"
 #include "utils/xml.h"
 
diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
new file mode 100644
index 00000000000..f4cd6138da3
--- /dev/null
+++ b/src/backend/commands/explain_state.c
@@ -0,0 +1,369 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.c
+ *	  Code for initializing and accessing ExplainState objects
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * In-core options have hard-coded fields inside ExplainState; e.g. if
+ * the user writes EXPLAIN (BUFFERS) then ExplainState's "buffers" member
+ * will be set to true. Extensions can also register options using
+ * RegisterExtensionExplainOption; so that e.g. EXPLAIN (BICYCLE 'red')
+ * will invoke a designated handler that knows what the legal values are
+ * for the BICYCLE option. However, it's not enough for an extension to be
+ * able to parse new options: it also needs a place to store the results
+ * of that parsing, and an ExplainState has no 'bicycle' field.
+ *
+ * To solve this problem, an ExplainState can contain an array of opaque
+ * pointers, one per extension. An extension can use GetExplainExtensionId
+ * to acquire an integer ID to acquire an offset into this array that is
+ * reserved for its exclusive use, and then use GetExplainExtensionState
+ * and SetExplainExtensionState to read and write its own private state
+ * within an ExplainState.
+ *
+ * Note that there is no requirement that the name of the option match
+ * the name of the extension; e.g. a pg_explain_conveyance extension could
+ * implement options for BICYCLE, MONORAIL, etc.
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/explain_state.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_state.h"
+
+typedef struct
+{
+	const char *option_name;
+	ExplainOptionHandler option_handler;
+} ExplainExtensionOption;
+
+static const char **ExplainExtensionNameArray = NULL;
+static int	ExplainExtensionNamesAssigned = 0;
+static int	ExplainExtensionNamesAllocated = 0;
+
+static ExplainExtensionOption *ExplainExtensionOptionArray = NULL;
+static int	ExplainExtensionOptionsAssigned = 0;
+static int	ExplainExtensionOptionsAllocated = 0;
+
+/*
+ * Create a new ExplainState struct initialized with default options.
+ */
+ExplainState *
+NewExplainState(void)
+{
+	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
+
+	/* Set default options (most fields can be left as zeroes). */
+	es->costs = true;
+	/* Prepare output buffer. */
+	es->str = makeStringInfo();
+
+	return es;
+}
+
+/*
+ * Parse a list of EXPLAIN options and update an ExplainState accordingly.
+ */
+void
+ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
+{
+	ListCell   *lc;
+	bool		timing_set = false;
+	bool		buffers_set = false;
+	bool		summary_set = false;
+
+	/* Parse options list. */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		if (strcmp(opt->defname, "analyze") == 0)
+			es->analyze = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "verbose") == 0)
+			es->verbose = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "costs") == 0)
+			es->costs = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "buffers") == 0)
+		{
+			buffers_set = true;
+			es->buffers = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "wal") == 0)
+			es->wal = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "settings") == 0)
+			es->settings = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "generic_plan") == 0)
+			es->generic = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "timing") == 0)
+		{
+			timing_set = true;
+			es->timing = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "summary") == 0)
+		{
+			summary_set = true;
+			es->summary = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "serialize") == 0)
+		{
+			if (opt->arg)
+			{
+				char	   *p = defGetString(opt);
+
+				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_NONE;
+				else if (strcmp(p, "text") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_TEXT;
+				else if (strcmp(p, "binary") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_BINARY;
+				else
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+									opt->defname, p),
+							 parser_errposition(pstate, opt->location)));
+			}
+			else
+			{
+				/* SERIALIZE without an argument is taken as 'text' */
+				es->serialize = EXPLAIN_SERIALIZE_TEXT;
+			}
+		}
+		else if (strcmp(opt->defname, "format") == 0)
+		{
+			char	   *p = defGetString(opt);
+
+			if (strcmp(p, "text") == 0)
+				es->format = EXPLAIN_FORMAT_TEXT;
+			else if (strcmp(p, "xml") == 0)
+				es->format = EXPLAIN_FORMAT_XML;
+			else if (strcmp(p, "json") == 0)
+				es->format = EXPLAIN_FORMAT_JSON;
+			else if (strcmp(p, "yaml") == 0)
+				es->format = EXPLAIN_FORMAT_YAML;
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+								opt->defname, p),
+						 parser_errposition(pstate, opt->location)));
+		}
+		else if (!ApplyExtensionExplainOption(es, opt, pstate))
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("unrecognized EXPLAIN option \"%s\"",
+							opt->defname),
+					 parser_errposition(pstate, opt->location)));
+	}
+
+	/* check that WAL is used with EXPLAIN ANALYZE */
+	if (es->wal && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
+
+	/* if the timing was not set explicitly, set default value */
+	es->timing = (timing_set) ? es->timing : es->analyze;
+
+	/* if the buffers was not set explicitly, set default value */
+	es->buffers = (buffers_set) ? es->buffers : es->analyze;
+
+	/* check that timing is used with EXPLAIN ANALYZE */
+	if (es->timing && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
+
+	/* check that serialize is used with EXPLAIN ANALYZE */
+	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
+
+	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
+	if (es->generic && es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
+
+	/* if the summary was not set explicitly, set default value */
+	es->summary = (summary_set) ? es->summary : es->analyze;
+}
+
+/*
+ * Map the name of an EXPLAIN extension to an integer ID.
+ *
+ * Within the lifetime of a particular backend, the same name will be mapped
+ * to the same ID every time. IDs are not stable across backends. Use the ID
+ * that you get from this function to call GetExplainExtensionState and
+ * SetExplainExtensionState.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+int
+GetExplainExtensionId(const char *extension_name)
+{
+	/* Search for an existing extension by this name; if found, return ID. */
+	for (int i = 0; i < ExplainExtensionNamesAssigned; ++i)
+		if (strcmp(ExplainExtensionNameArray[i], extension_name) == 0)
+			return i;
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionNameArray == NULL)
+	{
+		ExplainExtensionNamesAllocated = 16;
+		ExplainExtensionNameArray = (const char **)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionNamesAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionNamesAssigned >= ExplainExtensionNamesAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionNamesAssigned + 1);
+
+		ExplainExtensionNameArray = (const char **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(char *));
+		ExplainExtensionNamesAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	ExplainExtensionNameArray[ExplainExtensionNamesAssigned] = extension_name;
+	return ExplainExtensionNamesAssigned++;
+}
+
+/*
+ * Get extension-specific state from an ExplainState.
+ *
+ * See comments for SetExplainExtensionState, below.
+ */
+void *
+GetExplainExtensionState(ExplainState *es, int extension_id)
+{
+	Assert(extension_id >= 0);
+
+	if (extension_id >= es->extension_state_allocated)
+		return NULL;
+
+	return es->extension_state[extension_id];
+}
+
+/*
+ * Store extension-specific state into an ExplainState.
+ *
+ * To use this function, first obtain an integer extension_id using
+ * GetExplainExtensionId. Then use this function to store an opaque pointer
+ * in the ExplainState. Later, you can retrieve the opaque pointer using
+ * GetExplainExtensionState.
+ */
+void
+SetExplainExtensionState(ExplainState *es, int extension_id, void *opaque)
+{
+	Assert(extension_id >= 0);
+
+	/* If there is no array yet, create one. */
+	if (es->extension_state == NULL)
+	{
+		es->extension_state_allocated = 16;
+		es->extension_state =
+			palloc0(es->extension_state_allocated * sizeof(void *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (extension_id >= es->extension_state_allocated)
+	{
+		int			i;
+
+		i = pg_nextpower2_32(es->extension_state_allocated + 1);
+		es->extension_state = (void **)
+			repalloc(es->extension_state, i * sizeof(void *));
+		es->extension_state_allocated = i;
+	}
+
+	es->extension_state[extension_id] = opaque;
+}
+
+/*
+ * Register a new EXPLAIN option.
+ *
+ * When option_name is used as an EXPLAIN option, handler will be called and
+ * should update the ExplainState passed to it. See comments at top of file
+ * for a more detailed explanation.
+ *
+ * option_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+void
+RegisterExtensionExplainOption(const char *option_name,
+							   ExplainOptionHandler handler)
+{
+	ExplainExtensionOption *exopt;
+
+	/* Search for an existing option by this name; if found, update handler. */
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   option_name) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler = handler;
+			return;
+		}
+	}
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionOptionArray == NULL)
+	{
+		ExplainExtensionOptionsAllocated = 16;
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionOptionsAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionOptionsAssigned >= ExplainExtensionOptionsAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionOptionsAssigned + 1);
+
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			repalloc(ExplainExtensionOptionArray, i * sizeof(char *));
+		ExplainExtensionOptionsAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	exopt = &ExplainExtensionOptionArray[ExplainExtensionOptionsAssigned++];
+	exopt->option_name = option_name;
+	exopt->option_handler = handler;
+}
+
+/*
+ * Apply an EXPLAIN option registered by an extension.
+ *
+ * If no extension has registered the named option, returns false. Otherwise,
+ * calls the appropriate handler function and then returns true.
+ */
+bool
+ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index ce8d1ab8bac..dd4cde41d32 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -24,6 +24,7 @@ backend_sources += files(
   'explain.c',
   'explain_dr.c',
   'explain_format.c',
+  'explain_state.c',
   'extension.c',
   'foreigncmds.c',
   'functioncmds.c',
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 4d68d4d25c7..be92627bc8c 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "funcapi.h"
 #include "nodes/nodeFuncs.h"
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 64547bd9b9c..0ea313475f6 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -14,64 +14,9 @@
 #define EXPLAIN_H
 
 #include "executor/executor.h"
-#include "lib/stringinfo.h"
 #include "parser/parse_node.h"
 
-typedef enum ExplainSerializeOption
-{
-	EXPLAIN_SERIALIZE_NONE,
-	EXPLAIN_SERIALIZE_TEXT,
-	EXPLAIN_SERIALIZE_BINARY,
-} ExplainSerializeOption;
-
-typedef enum ExplainFormat
-{
-	EXPLAIN_FORMAT_TEXT,
-	EXPLAIN_FORMAT_XML,
-	EXPLAIN_FORMAT_JSON,
-	EXPLAIN_FORMAT_YAML,
-} ExplainFormat;
-
-typedef struct ExplainWorkersState
-{
-	int			num_workers;	/* # of worker processes the plan used */
-	bool	   *worker_inited;	/* per-worker state-initialized flags */
-	StringInfoData *worker_str; /* per-worker transient output buffers */
-	int		   *worker_state_save;	/* per-worker grouping state save areas */
-	StringInfo	prev_str;		/* saved output buffer while redirecting */
-} ExplainWorkersState;
-
-typedef struct ExplainState
-{
-	StringInfo	str;			/* output buffer */
-	/* options */
-	bool		verbose;		/* be verbose */
-	bool		analyze;		/* print actual times */
-	bool		costs;			/* print estimated costs */
-	bool		buffers;		/* print buffer usage */
-	bool		wal;			/* print WAL usage */
-	bool		timing;			/* print detailed node timing */
-	bool		summary;		/* print total planning and execution timing */
-	bool		memory;			/* print planner's memory usage information */
-	bool		settings;		/* print modified settings */
-	bool		generic;		/* generate a generic plan */
-	ExplainSerializeOption serialize;	/* serialize the query's output? */
-	ExplainFormat format;		/* output format */
-	/* state for output formatting --- not reset for each new plan tree */
-	int			indent;			/* current indentation level */
-	List	   *grouping_stack; /* format-specific grouping state */
-	/* state related to the current plan tree (filled by ExplainPrintPlan) */
-	PlannedStmt *pstmt;			/* top of plan */
-	List	   *rtable;			/* range table */
-	List	   *rtable_names;	/* alias names for RTEs */
-	List	   *deparse_cxt;	/* context list for deparsing expressions */
-	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
-	bool		hide_workers;	/* set if we find an invisible Gather */
-	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
-								 * entry */
-	/* state related to the current plan node */
-	ExplainWorkersState *workers_state; /* needed if parallel plan */
-} ExplainState;
+typedef struct ExplainState ExplainState;	/* defined in explain_state.h */
 
 /* Hook for plugins to get control in ExplainOneQuery() */
 typedef void (*ExplainOneQuery_hook_type) (Query *query,
@@ -95,8 +40,6 @@ extern void standard_ExplainOneQuery(Query *query, int cursorOptions,
 									 const char *queryString, ParamListInfo params,
 									 QueryEnvironment *queryEnv);
 
-extern ExplainState *NewExplainState(void);
-
 extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
 
 extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
new file mode 100644
index 00000000000..925097492b9
--- /dev/null
+++ b/src/include/commands/explain_state.h
@@ -0,0 +1,95 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.h
+ *	  prototypes for explain_state.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * src/include/commands/explain_state.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXPLAIN_STATE_H
+#define EXPLAIN_STATE_H
+
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+#include "parser/parse_node.h"
+
+typedef enum ExplainSerializeOption
+{
+	EXPLAIN_SERIALIZE_NONE,
+	EXPLAIN_SERIALIZE_TEXT,
+	EXPLAIN_SERIALIZE_BINARY,
+} ExplainSerializeOption;
+
+typedef enum ExplainFormat
+{
+	EXPLAIN_FORMAT_TEXT,
+	EXPLAIN_FORMAT_XML,
+	EXPLAIN_FORMAT_JSON,
+	EXPLAIN_FORMAT_YAML,
+} ExplainFormat;
+
+typedef struct ExplainWorkersState
+{
+	int			num_workers;	/* # of worker processes the plan used */
+	bool	   *worker_inited;	/* per-worker state-initialized flags */
+	StringInfoData *worker_str; /* per-worker transient output buffers */
+	int		   *worker_state_save;	/* per-worker grouping state save areas */
+	StringInfo	prev_str;		/* saved output buffer while redirecting */
+} ExplainWorkersState;
+
+typedef struct ExplainState
+{
+	StringInfo	str;			/* output buffer */
+	/* options */
+	bool		verbose;		/* be verbose */
+	bool		analyze;		/* print actual times */
+	bool		costs;			/* print estimated costs */
+	bool		buffers;		/* print buffer usage */
+	bool		wal;			/* print WAL usage */
+	bool		timing;			/* print detailed node timing */
+	bool		summary;		/* print total planning and execution timing */
+	bool		memory;			/* print planner's memory usage information */
+	bool		settings;		/* print modified settings */
+	bool		generic;		/* generate a generic plan */
+	ExplainSerializeOption serialize;	/* serialize the query's output? */
+	ExplainFormat format;		/* output format */
+	/* state for output formatting --- not reset for each new plan tree */
+	int			indent;			/* current indentation level */
+	List	   *grouping_stack; /* format-specific grouping state */
+	/* state related to the current plan tree (filled by ExplainPrintPlan) */
+	PlannedStmt *pstmt;			/* top of plan */
+	List	   *rtable;			/* range table */
+	List	   *rtable_names;	/* alias names for RTEs */
+	List	   *deparse_cxt;	/* context list for deparsing expressions */
+	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
+	bool		hide_workers;	/* set if we find an invisible Gather */
+	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
+								 * entry */
+	/* state related to the current plan node */
+	ExplainWorkersState *workers_state; /* needed if parallel plan */
+	/* extensions */
+	void	  **extension_state;
+	int			extension_state_allocated;
+} ExplainState;
+
+typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+
+extern ExplainState *NewExplainState(void);
+extern void ParseExplainOptionList(ExplainState *es, List *options,
+								   ParseState *pstate);
+
+extern int	GetExplainExtensionId(const char *extension_name);
+extern void *GetExplainExtensionState(ExplainState *es, int extension_id);
+extern void SetExplainExtensionState(ExplainState *es, int extension_id,
+									 void *opaque);
+
+extern void RegisterExtensionExplainOption(const char *option_name,
+										   ExplainOptionHandler handler);
+extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
+										ParseState *pstate);
+
+#endif							/* EXPLAIN_STATE_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9840060997f..e70c9368d94 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4244,3 +4244,5 @@ yyscan_t
 z_stream
 z_streamp
 zic_t
+ExplainExtensionOption
+ExplainOptionHandler
-- 
2.39.3 (Apple Git-145)

From aee7ec351ccdcedad1e35fbb531864acbb482b03 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:05:53 -0500
Subject: [PATCH v5 1/3] Make it possible for loadable modules to add EXPLAIN
 options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
---
 contrib/auto_explain/auto_explain.c   |   1 +
 contrib/file_fdw/file_fdw.c           |   3 +-
 contrib/postgres_fdw/postgres_fdw.c   |   2 +-
 src/backend/commands/Makefile         |   1 +
 src/backend/commands/createas.c       |   2 +
 src/backend/commands/explain.c        | 143 +---------
 src/backend/commands/explain_dr.c     |   1 +
 src/backend/commands/explain_format.c |   1 +
 src/backend/commands/explain_state.c  | 371 ++++++++++++++++++++++++++
 src/backend/commands/meson.build      |   1 +
 src/backend/commands/prepare.c        |   2 +
 src/backend/executor/execAmi.c        |   1 +
 src/backend/tcop/pquery.c             |   1 +
 src/include/commands/explain.h        |  80 +-----
 src/include/commands/explain_state.h  |  95 +++++++
 src/include/commands/prepare.h        |   3 +-
 src/include/nodes/extensible.h        |   2 +-
 src/tools/pgindent/typedefs.list      |   2 +
 18 files changed, 503 insertions(+), 209 deletions(-)
 create mode 100644 src/backend/commands/explain_state.c
 create mode 100644 src/include/commands/explain_state.h

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 7007a226c08..3b73bd19107 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -17,6 +17,7 @@
 #include "access/parallel.h"
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "utils/guc.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index bf707c812ed..56ececac70b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -24,9 +24,10 @@
 #include "commands/copy.h"
 #include "commands/copyfrom_internal.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/vacuum.h"
+#include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 1131a8bf77e..263c879026e 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -19,8 +19,8 @@
 #include "access/table.h"
 #include "catalog/pg_opfamily.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "executor/execAsync.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index 85cfea6fd71..cb2fbdc7c60 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -36,6 +36,7 @@ OBJS = \
 	explain.o \
 	explain_dr.o \
 	explain_format.o \
+	explain_state.o \
 	extension.o \
 	foreigncmds.o \
 	functioncmds.o \
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 44b4665ccd3..0a4155773eb 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -35,6 +35,8 @@
 #include "commands/prepare.h"
 #include "commands/tablecmds.h"
 #include "commands/view.h"
+#include "executor/execdesc.h"
+#include "executor/executor.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "nodes/queryjumble.h"
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d8a7232cedb..ac395bf1fdd 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -17,8 +17,10 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/defrem.h"
+#include "commands/explain.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -170,130 +172,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -354,22 +237,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	pfree(es->str->data);
 }
 
-/*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
 /*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
diff --git a/src/backend/commands/explain_dr.c b/src/backend/commands/explain_dr.c
index fb42bee6e72..5715546cf43 100644
--- a/src/backend/commands/explain_dr.c
+++ b/src/backend/commands/explain_dr.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_dr.h"
+#include "commands/explain_state.h"
 #include "libpq/pqformat.h"
 #include "libpq/protocol.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/commands/explain_format.c b/src/backend/commands/explain_format.c
index bccdd76a874..752691d56db 100644
--- a/src/backend/commands/explain_format.c
+++ b/src/backend/commands/explain_format.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "utils/json.h"
 #include "utils/xml.h"
 
diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
new file mode 100644
index 00000000000..1d4be3c18ac
--- /dev/null
+++ b/src/backend/commands/explain_state.c
@@ -0,0 +1,371 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.c
+ *	  Code for initializing and accessing ExplainState objects
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * In-core options have hard-coded fields inside ExplainState; e.g. if
+ * the user writes EXPLAIN (BUFFERS) then ExplainState's "buffers" member
+ * will be set to true. Extensions can also register options using
+ * RegisterExtensionExplainOption; so that e.g. EXPLAIN (BICYCLE 'red')
+ * will invoke a designated handler that knows what the legal values are
+ * for the BICYCLE option. However, it's not enough for an extension to be
+ * able to parse new options: it also needs a place to store the results
+ * of that parsing, and an ExplainState has no 'bicycle' field.
+ *
+ * To solve this problem, an ExplainState can contain an array of opaque
+ * pointers, one per extension. An extension can use GetExplainExtensionId
+ * to acquire an integer ID to acquire an offset into this array that is
+ * reserved for its exclusive use, and then use GetExplainExtensionState
+ * and SetExplainExtensionState to read and write its own private state
+ * within an ExplainState.
+ *
+ * Note that there is no requirement that the name of the option match
+ * the name of the extension; e.g. a pg_explain_conveyance extension could
+ * implement options for BICYCLE, MONORAIL, etc.
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/explain_state.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_state.h"
+
+typedef struct
+{
+	const char *option_name;
+	ExplainOptionHandler option_handler;
+} ExplainExtensionOption;
+
+static const char **ExplainExtensionNameArray = NULL;
+static int	ExplainExtensionNamesAssigned = 0;
+static int	ExplainExtensionNamesAllocated = 0;
+
+static ExplainExtensionOption *ExplainExtensionOptionArray = NULL;
+static int	ExplainExtensionOptionsAssigned = 0;
+static int	ExplainExtensionOptionsAllocated = 0;
+
+/*
+ * Create a new ExplainState struct initialized with default options.
+ */
+ExplainState *
+NewExplainState(void)
+{
+	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
+
+	/* Set default options (most fields can be left as zeroes). */
+	es->costs = true;
+	/* Prepare output buffer. */
+	es->str = makeStringInfo();
+
+	return es;
+}
+
+/*
+ * Parse a list of EXPLAIN options and update an ExplainState accordingly.
+ */
+void
+ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
+{
+	ListCell   *lc;
+	bool		timing_set = false;
+	bool		buffers_set = false;
+	bool		summary_set = false;
+
+	/* Parse options list. */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		if (strcmp(opt->defname, "analyze") == 0)
+			es->analyze = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "verbose") == 0)
+			es->verbose = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "costs") == 0)
+			es->costs = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "buffers") == 0)
+		{
+			buffers_set = true;
+			es->buffers = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "wal") == 0)
+			es->wal = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "settings") == 0)
+			es->settings = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "generic_plan") == 0)
+			es->generic = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "timing") == 0)
+		{
+			timing_set = true;
+			es->timing = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "summary") == 0)
+		{
+			summary_set = true;
+			es->summary = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "serialize") == 0)
+		{
+			if (opt->arg)
+			{
+				char	   *p = defGetString(opt);
+
+				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_NONE;
+				else if (strcmp(p, "text") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_TEXT;
+				else if (strcmp(p, "binary") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_BINARY;
+				else
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+									opt->defname, p),
+							 parser_errposition(pstate, opt->location)));
+			}
+			else
+			{
+				/* SERIALIZE without an argument is taken as 'text' */
+				es->serialize = EXPLAIN_SERIALIZE_TEXT;
+			}
+		}
+		else if (strcmp(opt->defname, "format") == 0)
+		{
+			char	   *p = defGetString(opt);
+
+			if (strcmp(p, "text") == 0)
+				es->format = EXPLAIN_FORMAT_TEXT;
+			else if (strcmp(p, "xml") == 0)
+				es->format = EXPLAIN_FORMAT_XML;
+			else if (strcmp(p, "json") == 0)
+				es->format = EXPLAIN_FORMAT_JSON;
+			else if (strcmp(p, "yaml") == 0)
+				es->format = EXPLAIN_FORMAT_YAML;
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+								opt->defname, p),
+						 parser_errposition(pstate, opt->location)));
+		}
+		else if (!ApplyExtensionExplainOption(es, opt, pstate))
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("unrecognized EXPLAIN option \"%s\"",
+							opt->defname),
+					 parser_errposition(pstate, opt->location)));
+	}
+
+	/* check that WAL is used with EXPLAIN ANALYZE */
+	if (es->wal && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
+
+	/* if the timing was not set explicitly, set default value */
+	es->timing = (timing_set) ? es->timing : es->analyze;
+
+	/* if the buffers was not set explicitly, set default value */
+	es->buffers = (buffers_set) ? es->buffers : es->analyze;
+
+	/* check that timing is used with EXPLAIN ANALYZE */
+	if (es->timing && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
+
+	/* check that serialize is used with EXPLAIN ANALYZE */
+	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
+
+	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
+	if (es->generic && es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
+
+	/* if the summary was not set explicitly, set default value */
+	es->summary = (summary_set) ? es->summary : es->analyze;
+}
+
+/*
+ * Map the name of an EXPLAIN extension to an integer ID.
+ *
+ * Within the lifetime of a particular backend, the same name will be mapped
+ * to the same ID every time. IDs are not stable across backends. Use the ID
+ * that you get from this function to call GetExplainExtensionState and
+ * SetExplainExtensionState.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+int
+GetExplainExtensionId(const char *extension_name)
+{
+	/* Search for an existing extension by this name; if found, return ID. */
+	for (int i = 0; i < ExplainExtensionNamesAssigned; ++i)
+		if (strcmp(ExplainExtensionNameArray[i], extension_name) == 0)
+			return i;
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionNameArray == NULL)
+	{
+		ExplainExtensionNamesAllocated = 16;
+		ExplainExtensionNameArray = (const char **)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionNamesAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionNamesAssigned >= ExplainExtensionNamesAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionNamesAssigned + 1);
+
+		ExplainExtensionNameArray = (const char **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(char *));
+		ExplainExtensionNamesAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	ExplainExtensionNameArray[ExplainExtensionNamesAssigned] = extension_name;
+	return ExplainExtensionNamesAssigned++;
+}
+
+/*
+ * Get extension-specific state from an ExplainState.
+ *
+ * See comments for SetExplainExtensionState, below.
+ */
+void *
+GetExplainExtensionState(ExplainState *es, int extension_id)
+{
+	Assert(extension_id >= 0);
+
+	if (extension_id >= es->extension_state_allocated)
+		return NULL;
+
+	return es->extension_state[extension_id];
+}
+
+/*
+ * Store extension-specific state into an ExplainState.
+ *
+ * To use this function, first obtain an integer extension_id using
+ * GetExplainExtensionId. Then use this function to store an opaque pointer
+ * in the ExplainState. Later, you can retrieve the opaque pointer using
+ * GetExplainExtensionState.
+ */
+void
+SetExplainExtensionState(ExplainState *es, int extension_id, void *opaque)
+{
+	Assert(extension_id >= 0);
+
+	/* If there is no array yet, create one. */
+	if (es->extension_state == NULL)
+	{
+		es->extension_state_allocated = 16;
+		es->extension_state =
+			palloc0(es->extension_state_allocated * sizeof(void *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (extension_id >= es->extension_state_allocated)
+	{
+		int			i;
+
+		i = pg_nextpower2_32(es->extension_state_allocated + 1);
+		es->extension_state = (void **)
+			repalloc0(es->extension_state,
+					  es->extension_state_allocated * sizeof(void *),
+					  i * sizeof(void *));
+		es->extension_state_allocated = i;
+	}
+
+	es->extension_state[extension_id] = opaque;
+}
+
+/*
+ * Register a new EXPLAIN option.
+ *
+ * When option_name is used as an EXPLAIN option, handler will be called and
+ * should update the ExplainState passed to it. See comments at top of file
+ * for a more detailed explanation.
+ *
+ * option_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+void
+RegisterExtensionExplainOption(const char *option_name,
+							   ExplainOptionHandler handler)
+{
+	ExplainExtensionOption *exopt;
+
+	/* Search for an existing option by this name; if found, update handler. */
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   option_name) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler = handler;
+			return;
+		}
+	}
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionOptionArray == NULL)
+	{
+		ExplainExtensionOptionsAllocated = 16;
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionOptionsAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionOptionsAssigned >= ExplainExtensionOptionsAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionOptionsAssigned + 1);
+
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			repalloc(ExplainExtensionOptionArray, i * sizeof(char *));
+		ExplainExtensionOptionsAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	exopt = &ExplainExtensionOptionArray[ExplainExtensionOptionsAssigned++];
+	exopt->option_name = option_name;
+	exopt->option_handler = handler;
+}
+
+/*
+ * Apply an EXPLAIN option registered by an extension.
+ *
+ * If no extension has registered the named option, returns false. Otherwise,
+ * calls the appropriate handler function and then returns true.
+ */
+bool
+ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index ce8d1ab8bac..dd4cde41d32 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -24,6 +24,7 @@ backend_sources += files(
   'explain.c',
   'explain_dr.c',
   'explain_format.c',
+  'explain_state.c',
   'extension.c',
   'foreigncmds.c',
   'functioncmds.c',
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 4d68d4d25c7..bf7d2b2309f 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -21,7 +21,9 @@
 #include "access/xact.h"
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
+#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "funcapi.h"
 #include "nodes/nodeFuncs.h"
diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c
index db525194554..1d0e8ad57b4 100644
--- a/src/backend/executor/execAmi.c
+++ b/src/backend/executor/execAmi.c
@@ -15,6 +15,7 @@
 #include "access/amapi.h"
 #include "access/htup_details.h"
 #include "catalog/pg_class.h"
+#include "executor/executor.h"
 #include "executor/nodeAgg.h"
 #include "executor/nodeAppend.h"
 #include "executor/nodeBitmapAnd.h"
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index dea24453a6c..8164d0fbb4f 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -20,6 +20,7 @@
 #include "access/xact.h"
 #include "commands/prepare.h"
 #include "executor/execdesc.h"
+#include "executor/executor.h"
 #include "executor/tstoreReceiver.h"
 #include "miscadmin.h"
 #include "pg_trace.h"
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 64547bd9b9c..783f67b468a 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -14,70 +14,15 @@
 #define EXPLAIN_H
 
 #include "executor/executor.h"
-#include "lib/stringinfo.h"
 #include "parser/parse_node.h"
 
-typedef enum ExplainSerializeOption
-{
-	EXPLAIN_SERIALIZE_NONE,
-	EXPLAIN_SERIALIZE_TEXT,
-	EXPLAIN_SERIALIZE_BINARY,
-} ExplainSerializeOption;
-
-typedef enum ExplainFormat
-{
-	EXPLAIN_FORMAT_TEXT,
-	EXPLAIN_FORMAT_XML,
-	EXPLAIN_FORMAT_JSON,
-	EXPLAIN_FORMAT_YAML,
-} ExplainFormat;
-
-typedef struct ExplainWorkersState
-{
-	int			num_workers;	/* # of worker processes the plan used */
-	bool	   *worker_inited;	/* per-worker state-initialized flags */
-	StringInfoData *worker_str; /* per-worker transient output buffers */
-	int		   *worker_state_save;	/* per-worker grouping state save areas */
-	StringInfo	prev_str;		/* saved output buffer while redirecting */
-} ExplainWorkersState;
-
-typedef struct ExplainState
-{
-	StringInfo	str;			/* output buffer */
-	/* options */
-	bool		verbose;		/* be verbose */
-	bool		analyze;		/* print actual times */
-	bool		costs;			/* print estimated costs */
-	bool		buffers;		/* print buffer usage */
-	bool		wal;			/* print WAL usage */
-	bool		timing;			/* print detailed node timing */
-	bool		summary;		/* print total planning and execution timing */
-	bool		memory;			/* print planner's memory usage information */
-	bool		settings;		/* print modified settings */
-	bool		generic;		/* generate a generic plan */
-	ExplainSerializeOption serialize;	/* serialize the query's output? */
-	ExplainFormat format;		/* output format */
-	/* state for output formatting --- not reset for each new plan tree */
-	int			indent;			/* current indentation level */
-	List	   *grouping_stack; /* format-specific grouping state */
-	/* state related to the current plan tree (filled by ExplainPrintPlan) */
-	PlannedStmt *pstmt;			/* top of plan */
-	List	   *rtable;			/* range table */
-	List	   *rtable_names;	/* alias names for RTEs */
-	List	   *deparse_cxt;	/* context list for deparsing expressions */
-	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
-	bool		hide_workers;	/* set if we find an invisible Gather */
-	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
-								 * entry */
-	/* state related to the current plan node */
-	ExplainWorkersState *workers_state; /* needed if parallel plan */
-} ExplainState;
+struct ExplainState;	/* defined in explain_state.h */
 
 /* Hook for plugins to get control in ExplainOneQuery() */
 typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   int cursorOptions,
 										   IntoClause *into,
-										   ExplainState *es,
+										   struct ExplainState *es,
 										   const char *queryString,
 										   ParamListInfo params,
 										   QueryEnvironment *queryEnv);
@@ -91,33 +36,34 @@ extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
 extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 						 ParamListInfo params, DestReceiver *dest);
 extern void standard_ExplainOneQuery(Query *query, int cursorOptions,
-									 IntoClause *into, ExplainState *es,
+									 IntoClause *into, struct ExplainState *es,
 									 const char *queryString, ParamListInfo params,
 									 QueryEnvironment *queryEnv);
 
-extern ExplainState *NewExplainState(void);
-
 extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
 
 extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
-							  ExplainState *es, ParseState *pstate,
+							  struct ExplainState *es, ParseState *pstate,
 							  ParamListInfo params);
 
 extern void ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 						   CachedPlanSource *plansource, int plan_index,
-						   IntoClause *into, ExplainState *es,
+						   IntoClause *into, struct ExplainState *es,
 						   const char *queryString,
 						   ParamListInfo params, QueryEnvironment *queryEnv,
 						   const instr_time *planduration,
 						   const BufferUsage *bufusage,
 						   const MemoryContextCounters *mem_counters);
 
-extern void ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc);
-extern void ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintPlan(struct ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintTriggers(struct ExplainState *es,
+								 QueryDesc *queryDesc);
 
-extern void ExplainPrintJITSummary(ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintJITSummary(struct ExplainState *es,
+								   QueryDesc *queryDesc);
 
-extern void ExplainQueryText(ExplainState *es, QueryDesc *queryDesc);
-extern void ExplainQueryParameters(ExplainState *es, ParamListInfo params, int maxlen);
+extern void ExplainQueryText(struct ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainQueryParameters(struct ExplainState *es,
+								   ParamListInfo params, int maxlen);
 
 #endif							/* EXPLAIN_H */
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
new file mode 100644
index 00000000000..925097492b9
--- /dev/null
+++ b/src/include/commands/explain_state.h
@@ -0,0 +1,95 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.h
+ *	  prototypes for explain_state.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * src/include/commands/explain_state.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXPLAIN_STATE_H
+#define EXPLAIN_STATE_H
+
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+#include "parser/parse_node.h"
+
+typedef enum ExplainSerializeOption
+{
+	EXPLAIN_SERIALIZE_NONE,
+	EXPLAIN_SERIALIZE_TEXT,
+	EXPLAIN_SERIALIZE_BINARY,
+} ExplainSerializeOption;
+
+typedef enum ExplainFormat
+{
+	EXPLAIN_FORMAT_TEXT,
+	EXPLAIN_FORMAT_XML,
+	EXPLAIN_FORMAT_JSON,
+	EXPLAIN_FORMAT_YAML,
+} ExplainFormat;
+
+typedef struct ExplainWorkersState
+{
+	int			num_workers;	/* # of worker processes the plan used */
+	bool	   *worker_inited;	/* per-worker state-initialized flags */
+	StringInfoData *worker_str; /* per-worker transient output buffers */
+	int		   *worker_state_save;	/* per-worker grouping state save areas */
+	StringInfo	prev_str;		/* saved output buffer while redirecting */
+} ExplainWorkersState;
+
+typedef struct ExplainState
+{
+	StringInfo	str;			/* output buffer */
+	/* options */
+	bool		verbose;		/* be verbose */
+	bool		analyze;		/* print actual times */
+	bool		costs;			/* print estimated costs */
+	bool		buffers;		/* print buffer usage */
+	bool		wal;			/* print WAL usage */
+	bool		timing;			/* print detailed node timing */
+	bool		summary;		/* print total planning and execution timing */
+	bool		memory;			/* print planner's memory usage information */
+	bool		settings;		/* print modified settings */
+	bool		generic;		/* generate a generic plan */
+	ExplainSerializeOption serialize;	/* serialize the query's output? */
+	ExplainFormat format;		/* output format */
+	/* state for output formatting --- not reset for each new plan tree */
+	int			indent;			/* current indentation level */
+	List	   *grouping_stack; /* format-specific grouping state */
+	/* state related to the current plan tree (filled by ExplainPrintPlan) */
+	PlannedStmt *pstmt;			/* top of plan */
+	List	   *rtable;			/* range table */
+	List	   *rtable_names;	/* alias names for RTEs */
+	List	   *deparse_cxt;	/* context list for deparsing expressions */
+	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
+	bool		hide_workers;	/* set if we find an invisible Gather */
+	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
+								 * entry */
+	/* state related to the current plan node */
+	ExplainWorkersState *workers_state; /* needed if parallel plan */
+	/* extensions */
+	void	  **extension_state;
+	int			extension_state_allocated;
+} ExplainState;
+
+typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+
+extern ExplainState *NewExplainState(void);
+extern void ParseExplainOptionList(ExplainState *es, List *options,
+								   ParseState *pstate);
+
+extern int	GetExplainExtensionId(const char *extension_name);
+extern void *GetExplainExtensionState(ExplainState *es, int extension_id);
+extern void SetExplainExtensionState(ExplainState *es, int extension_id,
+									 void *opaque);
+
+extern void RegisterExtensionExplainOption(const char *option_name,
+										   ExplainOptionHandler handler);
+extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
+										ParseState *pstate);
+
+#endif							/* EXPLAIN_STATE_H */
diff --git a/src/include/commands/prepare.h b/src/include/commands/prepare.h
index b9533f1af84..08daac8c926 100644
--- a/src/include/commands/prepare.h
+++ b/src/include/commands/prepare.h
@@ -13,8 +13,9 @@
 #ifndef PREPARE_H
 #define PREPARE_H
 
-#include "commands/explain.h"
+#include "commands/explain_state.h"
 #include "datatype/timestamp.h"
+#include "tcop/dest.h"
 #include "utils/plancache.h"
 
 /*
diff --git a/src/include/nodes/extensible.h b/src/include/nodes/extensible.h
index 552ce19bdd5..1129c4ba4b1 100644
--- a/src/include/nodes/extensible.h
+++ b/src/include/nodes/extensible.h
@@ -15,7 +15,7 @@
 #define EXTENSIBLE_H
 
 #include "access/parallel.h"
-#include "commands/explain.h"
+#include "commands/explain_state.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
 #include "nodes/plannodes.h"
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9840060997f..e70c9368d94 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4244,3 +4244,5 @@ yyscan_t
 z_stream
 z_streamp
 zic_t
+ExplainExtensionOption
+ExplainOptionHandler
-- 
2.39.3 (Apple Git-145)

From b6e44172cb60564af462b307e4d3fd95958c9b29 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:08:07 -0500
Subject: [PATCH v5 3/3] pg_overexplain: Additional EXPLAIN options for
 debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1576 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..b83a9542a6b
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e70c9368d94..838ea282326 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4246,3 +4246,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 1dcead8c2daa1f3194da67bac1e5d8eb8bd23ddc Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 6 Mar 2025 14:18:44 -0500
Subject: [PATCH v5 2/3] Add some new hooks so extensions can add details to
 EXPLAIN.

Specifically, add a per-node hook that is called after the per-node
information has been displayed but before we display children, and a
per-query hook that is called after existing query-level information
is printed. This assumes that extension-added information should
always go at the end rather than the beginning or the middle, but
that seems like an acceptable limitation for simplicity. It also
assumes that extensions will only want to add information, not remove
or reformat existing details; those also seem like acceptable
restrictions, at least for now.

If multiple EXPLAIN extensions are used, the order in which any
additional details are printed is likely to depend on the order in
which the modules are loaded. That doesn't seem great; so possibly
we should add some kind of registration interface that also allows
extensions to specify a priority, so that we can print details in
a predictable order. However, that would be less similar to existing
hooks, and perhaps not worth the complexity, so do this for now.
---
 src/backend/commands/explain.c | 13 +++++++++++++
 src/include/commands/explain.h | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index ac395bf1fdd..5150e7a6124 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -52,6 +52,9 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* per-plan and per-node hooks for plugins to print additional info */
+explain_per_plan_hook_type explain_per_plan_hook = NULL;
+explain_per_node_hook_type explain_per_node_hook = NULL;
 
 /*
  * Various places within need to convert bytes to kilobytes.  Round these up
@@ -648,6 +651,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 	if (es->serialize != EXPLAIN_SERIALIZE_NONE)
 		ExplainPrintSerialize(es, &serializeMetrics);
 
+	/* Allow plugins to print additional information */
+	if (explain_per_plan_hook)
+		(*explain_per_plan_hook) (plannedstmt, into, es, queryString,
+								  params, queryEnv);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -2308,6 +2316,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		ExplainFlushWorkersState(es);
 	es->workers_state = save_workers_state;
 
+	/* Allow plugins to print additional information */
+	if (explain_per_node_hook)
+		(*explain_per_node_hook) (planstate, ancestors, relationship,
+								  plan_name, es);
+
 	/*
 	 * If partition pruning was done during executor initialization, the
 	 * number of child plans we'll display below will be less than the number
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 783f67b468a..e8e92f966a1 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -28,6 +28,23 @@ typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   QueryEnvironment *queryEnv);
 extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 
+/* Hook for EXPLAIN plugins to print extra information for each plan */
+typedef void (*explain_per_plan_hook_type) (PlannedStmt *plannedstmt,
+											IntoClause *into,
+											struct ExplainState *es,
+											const char *queryString,
+											ParamListInfo params,
+											QueryEnvironment *queryEnv);
+extern PGDLLIMPORT explain_per_plan_hook_type explain_per_plan_hook;
+
+/* Hook for EXPLAIN plugins to print extra fields on individual plan nodes */
+typedef void (*explain_per_node_hook_type) (PlanState *planstate,
+											List *ancestors,
+											const char *relationship,
+											const char *plan_name,
+											struct ExplainState *es);
+extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
+
 /* Hook for plugins to get control in explain_get_index_name() */
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
-- 
2.39.3 (Apple Git-145)

From d4dc35957598499d54448d38211a021a4b95ce96 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 6 Mar 2025 14:18:44 -0500
Subject: [PATCH v6 2/3] Add some new hooks so extensions can add details to
 EXPLAIN.

Specifically, add a per-node hook that is called after the per-node
information has been displayed but before we display children, and a
per-query hook that is called after existing query-level information
is printed. This assumes that extension-added information should
always go at the end rather than the beginning or the middle, but
that seems like an acceptable limitation for simplicity. It also
assumes that extensions will only want to add information, not remove
or reformat existing details; those also seem like acceptable
restrictions, at least for now.

If multiple EXPLAIN extensions are used, the order in which any
additional details are printed is likely to depend on the order in
which the modules are loaded. That doesn't seem great; so possibly
we should add some kind of registration interface that also allows
extensions to specify a priority, so that we can print details in
a predictable order. However, that would be less similar to existing
hooks, and perhaps not worth the complexity, so do this for now.
---
 src/backend/commands/explain.c | 13 +++++++++++++
 src/include/commands/explain.h | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index ac395bf1fdd..5150e7a6124 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -52,6 +52,9 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* per-plan and per-node hooks for plugins to print additional info */
+explain_per_plan_hook_type explain_per_plan_hook = NULL;
+explain_per_node_hook_type explain_per_node_hook = NULL;
 
 /*
  * Various places within need to convert bytes to kilobytes.  Round these up
@@ -648,6 +651,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 	if (es->serialize != EXPLAIN_SERIALIZE_NONE)
 		ExplainPrintSerialize(es, &serializeMetrics);
 
+	/* Allow plugins to print additional information */
+	if (explain_per_plan_hook)
+		(*explain_per_plan_hook) (plannedstmt, into, es, queryString,
+								  params, queryEnv);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -2308,6 +2316,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		ExplainFlushWorkersState(es);
 	es->workers_state = save_workers_state;
 
+	/* Allow plugins to print additional information */
+	if (explain_per_node_hook)
+		(*explain_per_node_hook) (planstate, ancestors, relationship,
+								  plan_name, es);
+
 	/*
 	 * If partition pruning was done during executor initialization, the
 	 * number of child plans we'll display below will be less than the number
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 783f67b468a..e8e92f966a1 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -28,6 +28,23 @@ typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   QueryEnvironment *queryEnv);
 extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 
+/* Hook for EXPLAIN plugins to print extra information for each plan */
+typedef void (*explain_per_plan_hook_type) (PlannedStmt *plannedstmt,
+											IntoClause *into,
+											struct ExplainState *es,
+											const char *queryString,
+											ParamListInfo params,
+											QueryEnvironment *queryEnv);
+extern PGDLLIMPORT explain_per_plan_hook_type explain_per_plan_hook;
+
+/* Hook for EXPLAIN plugins to print extra fields on individual plan nodes */
+typedef void (*explain_per_node_hook_type) (PlanState *planstate,
+											List *ancestors,
+											const char *relationship,
+											const char *plan_name,
+											struct ExplainState *es);
+extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
+
 /* Hook for plugins to get control in explain_get_index_name() */
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
-- 
2.39.3 (Apple Git-145)

From d1c7aba9079a0871321a06ec7f6e4b96f8fafea8 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 7 Mar 2025 09:46:52 -0500
Subject: [PATCH v6 1/3] Make it possible for loadable modules to add EXPLAIN
 options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and can use SetExplainExtensionState
and GetExplainExtensionState to store related state inside the
ExplainState object and later retrieve it.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.
---
 contrib/auto_explain/auto_explain.c   |   1 +
 contrib/file_fdw/file_fdw.c           |   3 +-
 contrib/postgres_fdw/postgres_fdw.c   |   2 +-
 src/backend/commands/Makefile         |   1 +
 src/backend/commands/createas.c       |   2 +
 src/backend/commands/explain.c        | 143 +---------
 src/backend/commands/explain_dr.c     |   1 +
 src/backend/commands/explain_format.c |   1 +
 src/backend/commands/explain_state.c  | 371 ++++++++++++++++++++++++++
 src/backend/commands/meson.build      |   1 +
 src/backend/commands/prepare.c        |   2 +
 src/backend/executor/execAmi.c        |   1 +
 src/backend/tcop/pquery.c             |   1 +
 src/include/commands/explain.h        |  80 +-----
 src/include/commands/explain_state.h  |  96 +++++++
 src/include/commands/prepare.h        |   3 +-
 src/include/nodes/extensible.h        |   2 +-
 src/tools/pgindent/typedefs.list      |   2 +
 18 files changed, 504 insertions(+), 209 deletions(-)
 create mode 100644 src/backend/commands/explain_state.c
 create mode 100644 src/include/commands/explain_state.h

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 7007a226c08..3b73bd19107 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -17,6 +17,7 @@
 #include "access/parallel.h"
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "utils/guc.h"
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index bf707c812ed..56ececac70b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -24,9 +24,10 @@
 #include "commands/copy.h"
 #include "commands/copyfrom_internal.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/vacuum.h"
+#include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 1131a8bf77e..263c879026e 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -19,8 +19,8 @@
 #include "access/table.h"
 #include "catalog/pg_opfamily.h"
 #include "commands/defrem.h"
-#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "executor/execAsync.h"
 #include "foreign/fdwapi.h"
 #include "funcapi.h"
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index 85cfea6fd71..cb2fbdc7c60 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -36,6 +36,7 @@ OBJS = \
 	explain.o \
 	explain_dr.o \
 	explain_format.o \
+	explain_state.o \
 	extension.o \
 	foreigncmds.o \
 	functioncmds.o \
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 44b4665ccd3..0a4155773eb 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -35,6 +35,8 @@
 #include "commands/prepare.h"
 #include "commands/tablecmds.h"
 #include "commands/view.h"
+#include "executor/execdesc.h"
+#include "executor/executor.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "nodes/queryjumble.h"
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index d8a7232cedb..ac395bf1fdd 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -17,8 +17,10 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/defrem.h"
+#include "commands/explain.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -170,130 +172,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -354,22 +237,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	pfree(es->str->data);
 }
 
-/*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
 /*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
diff --git a/src/backend/commands/explain_dr.c b/src/backend/commands/explain_dr.c
index fb42bee6e72..5715546cf43 100644
--- a/src/backend/commands/explain_dr.c
+++ b/src/backend/commands/explain_dr.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_dr.h"
+#include "commands/explain_state.h"
 #include "libpq/pqformat.h"
 #include "libpq/protocol.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/commands/explain_format.c b/src/backend/commands/explain_format.c
index bccdd76a874..752691d56db 100644
--- a/src/backend/commands/explain_format.c
+++ b/src/backend/commands/explain_format.c
@@ -15,6 +15,7 @@
 
 #include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "utils/json.h"
 #include "utils/xml.h"
 
diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
new file mode 100644
index 00000000000..8e6eea20ba8
--- /dev/null
+++ b/src/backend/commands/explain_state.c
@@ -0,0 +1,371 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.c
+ *	  Code for initializing and accessing ExplainState objects
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * In-core options have hard-coded fields inside ExplainState; e.g. if
+ * the user writes EXPLAIN (BUFFERS) then ExplainState's "buffers" member
+ * will be set to true. Extensions can also register options using
+ * RegisterExtensionExplainOption; so that e.g. EXPLAIN (BICYCLE 'red')
+ * will invoke a designated handler that knows what the legal values are
+ * for the BICYCLE option. However, it's not enough for an extension to be
+ * able to parse new options: it also needs a place to store the results
+ * of that parsing, and an ExplainState has no 'bicycle' field.
+ *
+ * To solve this problem, an ExplainState can contain an array of opaque
+ * pointers, one per extension. GetExplainExtensionId generates integer
+ * IDs that are used as offests into this array. Extensions don't call this
+ * function direcrtly; instead, they call GetExplainExtensionState and
+ * SetExplainExtensionState which first map the provided name to an integer
+ * and then access the appropriate array offset.
+ *
+ * Note that there is no requirement that the name of the option match
+ * the name of the extension; e.g. a pg_explain_conveyance extension could
+ * implement options for BICYCLE, MONORAIL, etc.
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/explain_state.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_state.h"
+
+typedef struct
+{
+	const char *option_name;
+	ExplainOptionHandler option_handler;
+} ExplainExtensionOption;
+
+static int GetExplainExtensionId(const char *extension_name);
+
+static const char **ExplainExtensionNameArray = NULL;
+static int	ExplainExtensionNamesAssigned = 0;
+static int	ExplainExtensionNamesAllocated = 0;
+
+static ExplainExtensionOption *ExplainExtensionOptionArray = NULL;
+static int	ExplainExtensionOptionsAssigned = 0;
+static int	ExplainExtensionOptionsAllocated = 0;
+
+/*
+ * Create a new ExplainState struct initialized with default options.
+ */
+ExplainState *
+NewExplainState(void)
+{
+	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
+
+	/* Set default options (most fields can be left as zeroes). */
+	es->costs = true;
+	/* Prepare output buffer. */
+	es->str = makeStringInfo();
+
+	return es;
+}
+
+/*
+ * Parse a list of EXPLAIN options and update an ExplainState accordingly.
+ */
+void
+ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
+{
+	ListCell   *lc;
+	bool		timing_set = false;
+	bool		buffers_set = false;
+	bool		summary_set = false;
+
+	/* Parse options list. */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		if (strcmp(opt->defname, "analyze") == 0)
+			es->analyze = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "verbose") == 0)
+			es->verbose = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "costs") == 0)
+			es->costs = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "buffers") == 0)
+		{
+			buffers_set = true;
+			es->buffers = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "wal") == 0)
+			es->wal = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "settings") == 0)
+			es->settings = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "generic_plan") == 0)
+			es->generic = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "timing") == 0)
+		{
+			timing_set = true;
+			es->timing = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "summary") == 0)
+		{
+			summary_set = true;
+			es->summary = defGetBoolean(opt);
+		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
+		else if (strcmp(opt->defname, "serialize") == 0)
+		{
+			if (opt->arg)
+			{
+				char	   *p = defGetString(opt);
+
+				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_NONE;
+				else if (strcmp(p, "text") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_TEXT;
+				else if (strcmp(p, "binary") == 0)
+					es->serialize = EXPLAIN_SERIALIZE_BINARY;
+				else
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+									opt->defname, p),
+							 parser_errposition(pstate, opt->location)));
+			}
+			else
+			{
+				/* SERIALIZE without an argument is taken as 'text' */
+				es->serialize = EXPLAIN_SERIALIZE_TEXT;
+			}
+		}
+		else if (strcmp(opt->defname, "format") == 0)
+		{
+			char	   *p = defGetString(opt);
+
+			if (strcmp(p, "text") == 0)
+				es->format = EXPLAIN_FORMAT_TEXT;
+			else if (strcmp(p, "xml") == 0)
+				es->format = EXPLAIN_FORMAT_XML;
+			else if (strcmp(p, "json") == 0)
+				es->format = EXPLAIN_FORMAT_JSON;
+			else if (strcmp(p, "yaml") == 0)
+				es->format = EXPLAIN_FORMAT_YAML;
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
+								opt->defname, p),
+						 parser_errposition(pstate, opt->location)));
+		}
+		else if (!ApplyExtensionExplainOption(es, opt, pstate))
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("unrecognized EXPLAIN option \"%s\"",
+							opt->defname),
+					 parser_errposition(pstate, opt->location)));
+	}
+
+	/* check that WAL is used with EXPLAIN ANALYZE */
+	if (es->wal && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
+
+	/* if the timing was not set explicitly, set default value */
+	es->timing = (timing_set) ? es->timing : es->analyze;
+
+	/* if the buffers was not set explicitly, set default value */
+	es->buffers = (buffers_set) ? es->buffers : es->analyze;
+
+	/* check that timing is used with EXPLAIN ANALYZE */
+	if (es->timing && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
+
+	/* check that serialize is used with EXPLAIN ANALYZE */
+	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
+
+	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
+	if (es->generic && es->analyze)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
+
+	/* if the summary was not set explicitly, set default value */
+	es->summary = (summary_set) ? es->summary : es->analyze;
+}
+
+/*
+ * Get extension-specific state from an ExplainState.
+ *
+ * See comments for SetExplainExtensionState, below.
+ */
+void *
+GetExplainExtensionState(ExplainState *es, const char *extension_name)
+{
+	int		extension_id = GetExplainExtensionId(extension_name);
+
+	if (extension_id >= es->extension_state_allocated)
+		return NULL;
+
+	return es->extension_state[extension_id];
+}
+
+/*
+ * Store extension-specific state into an ExplainState.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed. You can retrieve the opaque pointer that you
+ * store with this extension later via GetExplainExtensionState.
+ */
+void
+SetExplainExtensionState(ExplainState *es, const char *extension_name,
+						 void *opaque)
+{
+	int		extension_id = GetExplainExtensionId(extension_name);
+
+	/* If there is no array yet, create one. */
+	if (es->extension_state == NULL)
+	{
+		es->extension_state_allocated = 16;
+		es->extension_state =
+			palloc0(es->extension_state_allocated * sizeof(void *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (extension_id >= es->extension_state_allocated)
+	{
+		int			i;
+
+		i = pg_nextpower2_32(es->extension_state_allocated + 1);
+		es->extension_state = (void **)
+			repalloc0(es->extension_state,
+					  es->extension_state_allocated * sizeof(void *),
+					  i * sizeof(void *));
+		es->extension_state_allocated = i;
+	}
+
+	es->extension_state[extension_id] = opaque;
+}
+
+/*
+ * Register a new EXPLAIN option.
+ *
+ * When option_name is used as an EXPLAIN option, handler will be called and
+ * should update the ExplainState passed to it. See comments at top of file
+ * for a more detailed explanation.
+ *
+ * option_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+void
+RegisterExtensionExplainOption(const char *option_name,
+							   ExplainOptionHandler handler)
+{
+	ExplainExtensionOption *exopt;
+
+	/* Search for an existing option by this name; if found, update handler. */
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   option_name) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler = handler;
+			return;
+		}
+	}
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionOptionArray == NULL)
+	{
+		ExplainExtensionOptionsAllocated = 16;
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionOptionsAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionOptionsAssigned >= ExplainExtensionOptionsAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionOptionsAssigned + 1);
+
+		ExplainExtensionOptionArray = (ExplainExtensionOption *)
+			repalloc(ExplainExtensionOptionArray, i * sizeof(char *));
+		ExplainExtensionOptionsAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	exopt = &ExplainExtensionOptionArray[ExplainExtensionOptionsAssigned++];
+	exopt->option_name = option_name;
+	exopt->option_handler = handler;
+}
+
+/*
+ * Apply an EXPLAIN option registered by an extension.
+ *
+ * If no extension has registered the named option, returns false. Otherwise,
+ * calls the appropriate handler function and then returns true.
+ */
+bool
+ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*
+ * Map the name of an EXPLAIN extension to an integer ID.
+ *
+ * Within the lifetime of a particular backend, the same name will be mapped
+ * to the same ID every time. IDs are not stable across backends.
+ *
+ * extension_name is assumed to be a constant string or allocated in storage
+ * that will never be freed.
+ */
+static int
+GetExplainExtensionId(const char *extension_name)
+{
+	/* Search for an existing extension by this name; if found, return ID. */
+	for (int i = 0; i < ExplainExtensionNamesAssigned; ++i)
+		if (strcmp(ExplainExtensionNameArray[i], extension_name) == 0)
+			return i;
+
+	/* If there is no array yet, create one. */
+	if (ExplainExtensionNameArray == NULL)
+	{
+		ExplainExtensionNamesAllocated = 16;
+		ExplainExtensionNameArray = (const char **)
+			MemoryContextAlloc(TopMemoryContext,
+							   ExplainExtensionNamesAllocated
+							   * sizeof(char *));
+	}
+
+	/* If there's an array but it's currently full, expand it. */
+	if (ExplainExtensionNamesAssigned >= ExplainExtensionNamesAllocated)
+	{
+		int			i = pg_nextpower2_32(ExplainExtensionNamesAssigned + 1);
+
+		ExplainExtensionNameArray = (const char **)
+			repalloc(ExplainExtensionNameArray, i * sizeof(char *));
+		ExplainExtensionNamesAllocated = i;
+	}
+
+	/* Assign and return new ID. */
+	ExplainExtensionNameArray[ExplainExtensionNamesAssigned] = extension_name;
+	return ExplainExtensionNamesAssigned++;
+}
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index ce8d1ab8bac..dd4cde41d32 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -24,6 +24,7 @@ backend_sources += files(
   'explain.c',
   'explain_dr.c',
   'explain_format.c',
+  'explain_state.c',
   'extension.c',
   'foreigncmds.c',
   'functioncmds.c',
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 4d68d4d25c7..bf7d2b2309f 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -21,7 +21,9 @@
 #include "access/xact.h"
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
+#include "commands/explain.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "funcapi.h"
 #include "nodes/nodeFuncs.h"
diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c
index db525194554..1d0e8ad57b4 100644
--- a/src/backend/executor/execAmi.c
+++ b/src/backend/executor/execAmi.c
@@ -15,6 +15,7 @@
 #include "access/amapi.h"
 #include "access/htup_details.h"
 #include "catalog/pg_class.h"
+#include "executor/executor.h"
 #include "executor/nodeAgg.h"
 #include "executor/nodeAppend.h"
 #include "executor/nodeBitmapAnd.h"
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index dea24453a6c..8164d0fbb4f 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -20,6 +20,7 @@
 #include "access/xact.h"
 #include "commands/prepare.h"
 #include "executor/execdesc.h"
+#include "executor/executor.h"
 #include "executor/tstoreReceiver.h"
 #include "miscadmin.h"
 #include "pg_trace.h"
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 64547bd9b9c..783f67b468a 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -14,70 +14,15 @@
 #define EXPLAIN_H
 
 #include "executor/executor.h"
-#include "lib/stringinfo.h"
 #include "parser/parse_node.h"
 
-typedef enum ExplainSerializeOption
-{
-	EXPLAIN_SERIALIZE_NONE,
-	EXPLAIN_SERIALIZE_TEXT,
-	EXPLAIN_SERIALIZE_BINARY,
-} ExplainSerializeOption;
-
-typedef enum ExplainFormat
-{
-	EXPLAIN_FORMAT_TEXT,
-	EXPLAIN_FORMAT_XML,
-	EXPLAIN_FORMAT_JSON,
-	EXPLAIN_FORMAT_YAML,
-} ExplainFormat;
-
-typedef struct ExplainWorkersState
-{
-	int			num_workers;	/* # of worker processes the plan used */
-	bool	   *worker_inited;	/* per-worker state-initialized flags */
-	StringInfoData *worker_str; /* per-worker transient output buffers */
-	int		   *worker_state_save;	/* per-worker grouping state save areas */
-	StringInfo	prev_str;		/* saved output buffer while redirecting */
-} ExplainWorkersState;
-
-typedef struct ExplainState
-{
-	StringInfo	str;			/* output buffer */
-	/* options */
-	bool		verbose;		/* be verbose */
-	bool		analyze;		/* print actual times */
-	bool		costs;			/* print estimated costs */
-	bool		buffers;		/* print buffer usage */
-	bool		wal;			/* print WAL usage */
-	bool		timing;			/* print detailed node timing */
-	bool		summary;		/* print total planning and execution timing */
-	bool		memory;			/* print planner's memory usage information */
-	bool		settings;		/* print modified settings */
-	bool		generic;		/* generate a generic plan */
-	ExplainSerializeOption serialize;	/* serialize the query's output? */
-	ExplainFormat format;		/* output format */
-	/* state for output formatting --- not reset for each new plan tree */
-	int			indent;			/* current indentation level */
-	List	   *grouping_stack; /* format-specific grouping state */
-	/* state related to the current plan tree (filled by ExplainPrintPlan) */
-	PlannedStmt *pstmt;			/* top of plan */
-	List	   *rtable;			/* range table */
-	List	   *rtable_names;	/* alias names for RTEs */
-	List	   *deparse_cxt;	/* context list for deparsing expressions */
-	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
-	bool		hide_workers;	/* set if we find an invisible Gather */
-	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
-								 * entry */
-	/* state related to the current plan node */
-	ExplainWorkersState *workers_state; /* needed if parallel plan */
-} ExplainState;
+struct ExplainState;	/* defined in explain_state.h */
 
 /* Hook for plugins to get control in ExplainOneQuery() */
 typedef void (*ExplainOneQuery_hook_type) (Query *query,
 										   int cursorOptions,
 										   IntoClause *into,
-										   ExplainState *es,
+										   struct ExplainState *es,
 										   const char *queryString,
 										   ParamListInfo params,
 										   QueryEnvironment *queryEnv);
@@ -91,33 +36,34 @@ extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
 extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 						 ParamListInfo params, DestReceiver *dest);
 extern void standard_ExplainOneQuery(Query *query, int cursorOptions,
-									 IntoClause *into, ExplainState *es,
+									 IntoClause *into, struct ExplainState *es,
 									 const char *queryString, ParamListInfo params,
 									 QueryEnvironment *queryEnv);
 
-extern ExplainState *NewExplainState(void);
-
 extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
 
 extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
-							  ExplainState *es, ParseState *pstate,
+							  struct ExplainState *es, ParseState *pstate,
 							  ParamListInfo params);
 
 extern void ExplainOnePlan(PlannedStmt *plannedstmt, CachedPlan *cplan,
 						   CachedPlanSource *plansource, int plan_index,
-						   IntoClause *into, ExplainState *es,
+						   IntoClause *into, struct ExplainState *es,
 						   const char *queryString,
 						   ParamListInfo params, QueryEnvironment *queryEnv,
 						   const instr_time *planduration,
 						   const BufferUsage *bufusage,
 						   const MemoryContextCounters *mem_counters);
 
-extern void ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc);
-extern void ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintPlan(struct ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintTriggers(struct ExplainState *es,
+								 QueryDesc *queryDesc);
 
-extern void ExplainPrintJITSummary(ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainPrintJITSummary(struct ExplainState *es,
+								   QueryDesc *queryDesc);
 
-extern void ExplainQueryText(ExplainState *es, QueryDesc *queryDesc);
-extern void ExplainQueryParameters(ExplainState *es, ParamListInfo params, int maxlen);
+extern void ExplainQueryText(struct ExplainState *es, QueryDesc *queryDesc);
+extern void ExplainQueryParameters(struct ExplainState *es,
+								   ParamListInfo params, int maxlen);
 
 #endif							/* EXPLAIN_H */
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
new file mode 100644
index 00000000000..6c161bfb615
--- /dev/null
+++ b/src/include/commands/explain_state.h
@@ -0,0 +1,96 @@
+/*-------------------------------------------------------------------------
+ *
+ * explain_state.h
+ *	  prototypes for explain_state.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * src/include/commands/explain_state.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EXPLAIN_STATE_H
+#define EXPLAIN_STATE_H
+
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+#include "parser/parse_node.h"
+
+typedef enum ExplainSerializeOption
+{
+	EXPLAIN_SERIALIZE_NONE,
+	EXPLAIN_SERIALIZE_TEXT,
+	EXPLAIN_SERIALIZE_BINARY,
+} ExplainSerializeOption;
+
+typedef enum ExplainFormat
+{
+	EXPLAIN_FORMAT_TEXT,
+	EXPLAIN_FORMAT_XML,
+	EXPLAIN_FORMAT_JSON,
+	EXPLAIN_FORMAT_YAML,
+} ExplainFormat;
+
+typedef struct ExplainWorkersState
+{
+	int			num_workers;	/* # of worker processes the plan used */
+	bool	   *worker_inited;	/* per-worker state-initialized flags */
+	StringInfoData *worker_str; /* per-worker transient output buffers */
+	int		   *worker_state_save;	/* per-worker grouping state save areas */
+	StringInfo	prev_str;		/* saved output buffer while redirecting */
+} ExplainWorkersState;
+
+typedef struct ExplainState
+{
+	StringInfo	str;			/* output buffer */
+	/* options */
+	bool		verbose;		/* be verbose */
+	bool		analyze;		/* print actual times */
+	bool		costs;			/* print estimated costs */
+	bool		buffers;		/* print buffer usage */
+	bool		wal;			/* print WAL usage */
+	bool		timing;			/* print detailed node timing */
+	bool		summary;		/* print total planning and execution timing */
+	bool		memory;			/* print planner's memory usage information */
+	bool		settings;		/* print modified settings */
+	bool		generic;		/* generate a generic plan */
+	ExplainSerializeOption serialize;	/* serialize the query's output? */
+	ExplainFormat format;		/* output format */
+	/* state for output formatting --- not reset for each new plan tree */
+	int			indent;			/* current indentation level */
+	List	   *grouping_stack; /* format-specific grouping state */
+	/* state related to the current plan tree (filled by ExplainPrintPlan) */
+	PlannedStmt *pstmt;			/* top of plan */
+	List	   *rtable;			/* range table */
+	List	   *rtable_names;	/* alias names for RTEs */
+	List	   *deparse_cxt;	/* context list for deparsing expressions */
+	Bitmapset  *printed_subplans;	/* ids of SubPlans we've printed */
+	bool		hide_workers;	/* set if we find an invisible Gather */
+	int			rtable_size;	/* length of rtable excluding the RTE_GROUP
+								 * entry */
+	/* state related to the current plan node */
+	ExplainWorkersState *workers_state; /* needed if parallel plan */
+	/* extensions */
+	void	  **extension_state;
+	int			extension_state_allocated;
+} ExplainState;
+
+typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+
+extern ExplainState *NewExplainState(void);
+extern void ParseExplainOptionList(ExplainState *es, List *options,
+								   ParseState *pstate);
+
+extern void *GetExplainExtensionState(ExplainState *es,
+									  const char *extension_name);
+extern void SetExplainExtensionState(ExplainState *es,
+									 const char *extension_name,
+									 void *opaque);
+
+extern void RegisterExtensionExplainOption(const char *option_name,
+										   ExplainOptionHandler handler);
+extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
+										ParseState *pstate);
+
+#endif							/* EXPLAIN_STATE_H */
diff --git a/src/include/commands/prepare.h b/src/include/commands/prepare.h
index b9533f1af84..08daac8c926 100644
--- a/src/include/commands/prepare.h
+++ b/src/include/commands/prepare.h
@@ -13,8 +13,9 @@
 #ifndef PREPARE_H
 #define PREPARE_H
 
-#include "commands/explain.h"
+#include "commands/explain_state.h"
 #include "datatype/timestamp.h"
+#include "tcop/dest.h"
 #include "utils/plancache.h"
 
 /*
diff --git a/src/include/nodes/extensible.h b/src/include/nodes/extensible.h
index 552ce19bdd5..1129c4ba4b1 100644
--- a/src/include/nodes/extensible.h
+++ b/src/include/nodes/extensible.h
@@ -15,7 +15,7 @@
 #define EXTENSIBLE_H
 
 #include "access/parallel.h"
-#include "commands/explain.h"
+#include "commands/explain_state.h"
 #include "nodes/execnodes.h"
 #include "nodes/pathnodes.h"
 #include "nodes/plannodes.h"
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9840060997f..e70c9368d94 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4244,3 +4244,5 @@ yyscan_t
 z_stream
 z_streamp
 zic_t
+ExplainExtensionOption
+ExplainOptionHandler
-- 
2.39.3 (Apple Git-145)

From b9c8d30153194979ced92e598f40c37e631c5efd Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 7 Mar 2025 09:54:39 -0500
Subject: [PATCH v6 3/3] pg_overexplain: Additional EXPLAIN options for
 debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 759 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1572 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..e03b77df773
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,759 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, "pg_overexplain");
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, "pg_overexplain", options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, "pg_overexplain");
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, "pg_overexplain");
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e70c9368d94..838ea282326 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4246,3 +4246,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From d4350df06cfeb0d9d5d7fe99b898c1a7ef237c97 Mon Sep 17 00:00:00 2001
From: Sami Imseih <simseih@amazon.com>
Date: Thu, 13 Mar 2025 16:15:59 -0500
Subject: [PATCH 1/1] Add a handler to validate an EXPLAIN option defined by an
 extension.

---
 src/backend/commands/explain_state.c | 28 +++++++++++++++++++++++++++-
 src/include/commands/explain_state.h | 11 ++++++++++-
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
index 8e6eea20ba8..a052355f3c5 100644
--- a/src/backend/commands/explain_state.c
+++ b/src/backend/commands/explain_state.c
@@ -198,6 +198,14 @@ ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
 
 	/* if the summary was not set explicitly, set default value */
 	es->summary = (summary_set) ? es->summary : es->analyze;
+
+	/* Validate the extension options */
+	foreach(lc, options)
+	{
+		DefElem    *opt = (DefElem *) lfirst(lc);
+
+		ValidateExtensionExplainOption(es, opt);
+	}
 }
 
 /*
@@ -320,7 +328,7 @@ ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
 		if (strcmp(ExplainExtensionOptionArray[i].option_name,
 				   opt->defname) == 0)
 		{
-			ExplainExtensionOptionArray[i].option_handler(es, opt, pstate);
+			ExplainExtensionOptionArray[i].option_handler.apply(es, opt, pstate);
 			return true;
 		}
 	}
@@ -328,6 +336,24 @@ ApplyExtensionExplainOption(ExplainState *es, DefElem *opt, ParseState *pstate)
 	return false;
 }
 
+/*
+ * Validate an EXPLAIN option registered by an extension.
+ *
+ * Should only be called after ApplyExtensionExplainOption.
+ */
+void
+ValidateExtensionExplainOption(ExplainState *es, DefElem *opt)
+{
+	for (int i = 0; i < ExplainExtensionOptionsAssigned; ++i)
+	{
+		if (strcmp(ExplainExtensionOptionArray[i].option_name,
+				   opt->defname) == 0)
+		{
+			ExplainExtensionOptionArray[i].option_handler.validate(es, opt);
+		}
+	}
+}
+
 /*
  * Map the name of an EXPLAIN extension to an integer ID.
  *
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
index 6c161bfb615..6850d4c06b4 100644
--- a/src/include/commands/explain_state.h
+++ b/src/include/commands/explain_state.h
@@ -76,7 +76,15 @@ typedef struct ExplainState
 	int			extension_state_allocated;
 } ExplainState;
 
-typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
+typedef void (*ExplainOptionApply) (ExplainState *, DefElem *, ParseState *);
+typedef void (*ExplainOptionValidate) (ExplainState *, DefElem *);
+
+
+typedef struct ExplainOptionHandler
+{
+	ExplainOptionApply apply;
+	ExplainOptionValidate validate;
+} ExplainOptionHandler;
 
 extern ExplainState *NewExplainState(void);
 extern void ParseExplainOptionList(ExplainState *es, List *options,
@@ -92,5 +100,6 @@ extern void RegisterExtensionExplainOption(const char *option_name,
 										   ExplainOptionHandler handler);
 extern bool ApplyExtensionExplainOption(ExplainState *es, DefElem *opt,
 										ParseState *pstate);
+extern void ValidateExtensionExplainOption(ExplainState *es, DefElem *opt);
 
 #endif							/* EXPLAIN_STATE_H */
-- 
2.39.5 (Apple Git-154)

From 40d93dcb2c61d49d1b4c18b783d7be59ac65dbb1 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:08:07 -0500
Subject: [PATCH v7] pg_overexplain: Additional EXPLAIN options for debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 476 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1576 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..5f333d12d51
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,476 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(43 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..b83a9542a6b
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index c04a47cf222..49fd328cc7c 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4273,3 +4273,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 10135db80e674e2f0dfe83e4ac3231ea7c9ff987 Mon Sep 17 00:00:00 2001
From: Sami Imseih <simseih@amazon.com>
Date: Tue, 18 Mar 2025 13:17:19 -0400
Subject: [PATCH v1 1/1] Add new hooks for performing additional EXPLAIN
 options validation

c65bc2e1d1 made it possible for loadable modules to define EXPLAIN
options. This patch introduces a new hook to allow a module to
perform validation of options against other options.

Discussion: https://www.postgresql.org/message-id/CAA5RZ0tM8jEe_LSjjrTux9TbTpLex-PFQtSuVcfXCWT%3DN%2Bthug%40mail.gmail.com
---
 src/backend/commands/explain_state.c | 7 +++++++
 src/include/commands/explain.h       | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
index 1d4be3c18ac..783004b3a05 100644
--- a/src/backend/commands/explain_state.c
+++ b/src/backend/commands/explain_state.c
@@ -37,6 +37,9 @@
 #include "commands/explain.h"
 #include "commands/explain_state.h"
 
+/* Hook to perform additional EXPLAIN options validation */
+explain_validate_options_hook_type explain_validate_options_hook = NULL;
+
 typedef struct
 {
 	const char *option_name;
@@ -196,6 +199,10 @@ ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
 
 	/* if the summary was not set explicitly, set default value */
 	es->summary = (summary_set) ? es->summary : es->analyze;
+
+	/* plugin specific option validation */
+	if (explain_validate_options_hook)
+		(*explain_validate_options_hook)(es);
 }
 
 /*
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 387839eb5d2..26b29677967 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -49,6 +49,14 @@ extern PGDLLIMPORT explain_per_node_hook_type explain_per_node_hook;
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
 
+/*
+ * Hook to perform additional EXPLAIN options validation.
+ *
+ * Returns void as we expect the plugin to throw an error when
+ * a validation fails.
+ */
+typedef void (*explain_validate_options_hook_type) (struct ExplainState *es);
+extern PGDLLIMPORT explain_validate_options_hook_type explain_validate_options_hook;
 
 extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 						 ParamListInfo params, DestReceiver *dest);
-- 
2.39.5 (Apple Git-154)

From f25fcd6965d785bc4f4e0676376f26a63bfe98d4 Mon Sep 17 00:00:00 2001
From: Sami Imseih <simseih@amazon.com>
Date: Tue, 18 Mar 2025 13:17:19 -0400
Subject: [PATCH v2 1/1] Add new hooks for performing additional EXPLAIN
 options validation

c65bc2e1d1 made it possible for loadable modules to define EXPLAIN
options. This patch introduces a new hook to allow a module to
perform validation of options against other options.

Discussion: https://www.postgresql.org/message-id/CAA5RZ0tM8jEe_LSjjrTux9TbTpLex-PFQtSuVcfXCWT%3DN%2Bthug%40mail.gmail.com
---
 src/backend/commands/explain_state.c | 7 +++++++
 src/include/commands/explain_state.h | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
index 1d4be3c18ac..8fe1ca5c73e 100644
--- a/src/backend/commands/explain_state.c
+++ b/src/backend/commands/explain_state.c
@@ -37,6 +37,9 @@
 #include "commands/explain.h"
 #include "commands/explain_state.h"
 
+/* Hook to perform additional EXPLAIN options validation */
+explain_validate_options_hook_type explain_validate_options_hook = NULL;
+
 typedef struct
 {
 	const char *option_name;
@@ -196,6 +199,10 @@ ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
 
 	/* if the summary was not set explicitly, set default value */
 	es->summary = (summary_set) ? es->summary : es->analyze;
+
+	/* plugin specific option validation */
+	if (explain_validate_options_hook)
+		(*explain_validate_options_hook)(es, options, pstate);
 }
 
 /*
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
index 925097492b9..32728f5d1a1 100644
--- a/src/include/commands/explain_state.h
+++ b/src/include/commands/explain_state.h
@@ -78,6 +78,11 @@ typedef struct ExplainState
 
 typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
 
+/* Hook to perform additional EXPLAIN options validation */
+typedef void (*explain_validate_options_hook_type) (struct ExplainState *es, List *options,
+													ParseState *pstate);
+extern PGDLLIMPORT explain_validate_options_hook_type explain_validate_options_hook;
+
 extern ExplainState *NewExplainState(void);
 extern void ParseExplainOptionList(ExplainState *es, List *options,
 								   ParseState *pstate);
-- 
2.39.5 (Apple Git-154)

From a599fb848e2f1b6c8e1dc4354f4123e9904bdb3b Mon Sep 17 00:00:00 2001
From: Sami Imseih <simseih@amazon.com>
Date: Tue, 18 Mar 2025 13:17:19 -0400
Subject: [PATCH v3 1/1] Add new hooks for performing additional EXPLAIN
 options validation

c65bc2e1d1 made it possible for loadable modules to define EXPLAIN
options. This patch introduces a new hook to allow a module to
perform validation of options against other options.

Discussion: https://www.postgresql.org/message-id/CAA5RZ0tM8jEe_LSjjrTux9TbTpLex-PFQtSuVcfXCWT%3DN%2Bthug%40mail.gmail.com
---
 src/backend/commands/explain_state.c | 7 +++++++
 src/include/commands/explain_state.h | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/src/backend/commands/explain_state.c b/src/backend/commands/explain_state.c
index 1d4be3c18ac..60d98d63a62 100644
--- a/src/backend/commands/explain_state.c
+++ b/src/backend/commands/explain_state.c
@@ -37,6 +37,9 @@
 #include "commands/explain.h"
 #include "commands/explain_state.h"
 
+/* Hook to perform additional EXPLAIN options validation */
+explain_validate_options_hook_type explain_validate_options_hook = NULL;
+
 typedef struct
 {
 	const char *option_name;
@@ -196,6 +199,10 @@ ParseExplainOptionList(ExplainState *es, List *options, ParseState *pstate)
 
 	/* if the summary was not set explicitly, set default value */
 	es->summary = (summary_set) ? es->summary : es->analyze;
+
+	/* plugin specific option validation */
+	if (explain_validate_options_hook)
+		(*explain_validate_options_hook) (es, options, pstate);
 }
 
 /*
diff --git a/src/include/commands/explain_state.h b/src/include/commands/explain_state.h
index 925097492b9..32728f5d1a1 100644
--- a/src/include/commands/explain_state.h
+++ b/src/include/commands/explain_state.h
@@ -78,6 +78,11 @@ typedef struct ExplainState
 
 typedef void (*ExplainOptionHandler) (ExplainState *, DefElem *, ParseState *);
 
+/* Hook to perform additional EXPLAIN options validation */
+typedef void (*explain_validate_options_hook_type) (struct ExplainState *es, List *options,
+													ParseState *pstate);
+extern PGDLLIMPORT explain_validate_options_hook_type explain_validate_options_hook;
+
 extern ExplainState *NewExplainState(void);
 extern void ParseExplainOptionList(ExplainState *es, List *options,
 								   ParseState *pstate);
-- 
2.47.1

From 76d0b119ecc0e72972e7c9680c6aedf3d3c57a58 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 5 Mar 2025 16:08:07 -0500
Subject: [PATCH v8] pg_overexplain: Additional EXPLAIN options for debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 480 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 101 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 178 ++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1580 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..c7257e97dac
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,480 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Index Searches: 1
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Index Searches: 1
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Index Searches: 8
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Index Searches: 8
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(47 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..b83a9542a6b
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *, DefElem *,
+									  ParseState *);
+static void overexplain_range_table_handler(ExplainState *, DefElem *,
+											ParseState *);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..7051dd0603e
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,101 @@
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..476dea883ed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,178 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; overexplain map information and utilities</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command> with
+  new options that provide additional output.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from the
+   plan tree that is not normally shown because it is not expected to be of general
+   interest. For each individual plan node, it will display the following fields.
+   See <literal>Plan</literal> in <literal>nodes/plannodes.h</literal> for additional
+   documentation of these fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command> determines
+     whether a node is disabled by checking whether the node's count of disabled
+     nodes is larger than the sum of the counts for the underlying nodes. This option
+     shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for a plan
+     tree node to appear beneath a <literal>Gather</literal> or <literal>Gather
+     Merge</literal> node, regardless of whether it is actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be unique for
+     every node in the plan tree. It is used to coordinate parallel query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information about
+     which numbered parameters affect this plan node or its children. In text mode,
+     these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the following
+   fields. See <literal>PlannedStmt</literal> in <literal>nodes/plannodes.h</literal>
+   for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure member
+     names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string supplied to
+     the planner where this query's text can be found. May be <literal>Unknown</literal>
+     in some contexts. Otherwise, may be <literal>NNN to end</literal> for some integer
+     <literal>NNN</literal> or <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the plan tree
+   specifically concerning the query's range table. Range table entries correspond
+   roughly to items appearing in the query's <literal>FROM</literal> clause, but with
+   numerous exceptions. For example, subqueries that are proved unnecessary may be
+   deleted from the range table entirely, while inheritance expansion adds range table
+   entries for child tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a range table
+   index, or RTI. Plan nodes that reference one or more RTIs will be labelled
+   accordingly, using one of the following fields: <literal>Scan RTI</literal>,
+   <literal>Nominal RTI</literal>, <literal>Exclude Relation RTI</literal>,
+   <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes that
+   are needed for various purposes. These lists will be displayed once per query,
+   labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only displayed if
+   they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option will
+   display a dump of the query's entire range table. Each range table entry is labelled
+   with the appropriate range table index, the kind of range table entry (e.g.
+   <literal>relation</literal>, <literal>subquery</literal>, or
+   <literal>join</literal>), followed by the contents of various range table entry
+   fields that are not normally part of <literal>EXPLAIN</literal> output. Some of
+   these fields are only displayed for certain kinds of range table entries. For
+   example, <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries of type
+   <literal>cte</literal>.
+  </para>
+
+  <para>
+   In general, the information provided by this option is intended for developers,
+   rather than end-users. Therefore, it is likely to be necessary to consult the
+   source code to fully understand what this option is telling you. A good place to
+   start is the definition of <literal>RangeTblEntry</literal> in
+   <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index bfa276d2d35..38432f4e27b 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4276,3 +4276,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 25045d8476a6116bb2bf6777bedd41c7986528ff Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 21 Mar 2025 15:53:12 -0400
Subject: [PATCH v9] pg_overexplain: Additional EXPLAIN options for debugging.

There's a fair amount of information in the Plan and PlanState trees
that isn't printed by any existing EXPLAIN option. This means that,
when working on the planner, it's often necessary to rely on facilities
such as debug_print_plan, which produce excessively voluminous
output. Hence, use the new EXPLAIN extension facilities to implement
EXPLAIN (DEBUG) and EXPLAIN (RANGE_TABLE) as extensions to the core
EXPLAIN facility.

A great deal more could be done here, and the specific choices about
what to print and how are definitely arguable, but this is at least
a starting point for discussion and a jumping-off point for possible
future improvements.

Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
---
 contrib/Makefile                              |   1 +
 contrib/meson.build                           |   1 +
 contrib/pg_overexplain/.gitignore             |   4 +
 contrib/pg_overexplain/Makefile               |  21 +
 .../expected/pg_overexplain.out               | 483 +++++++++++
 contrib/pg_overexplain/meson.build            |  28 +
 contrib/pg_overexplain/pg_overexplain.c       | 763 ++++++++++++++++++
 contrib/pg_overexplain/sql/pg_overexplain.sql | 105 +++
 doc/src/sgml/contrib.sgml                     |   1 +
 doc/src/sgml/filelist.sgml                    |   1 +
 doc/src/sgml/pgoverexplain.sgml               | 186 +++++
 src/tools/pgindent/typedefs.list              |   1 +
 12 files changed, 1595 insertions(+)
 create mode 100644 contrib/pg_overexplain/.gitignore
 create mode 100644 contrib/pg_overexplain/Makefile
 create mode 100644 contrib/pg_overexplain/expected/pg_overexplain.out
 create mode 100644 contrib/pg_overexplain/meson.build
 create mode 100644 contrib/pg_overexplain/pg_overexplain.c
 create mode 100644 contrib/pg_overexplain/sql/pg_overexplain.sql
 create mode 100644 doc/src/sgml/pgoverexplain.sgml

diff --git a/contrib/Makefile b/contrib/Makefile
index 952855d9b61..2f0a88d3f77 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -33,6 +33,7 @@ SUBDIRS = \
 		pg_buffercache	\
 		pg_freespacemap \
 		pg_logicalinspect \
+		pg_overexplain \
 		pg_prewarm	\
 		pg_stat_statements \
 		pg_surgery	\
diff --git a/contrib/meson.build b/contrib/meson.build
index 1ba73ebd67a..ed30ee7d639 100644
--- a/contrib/meson.build
+++ b/contrib/meson.build
@@ -47,6 +47,7 @@ subdir('pg_buffercache')
 subdir('pgcrypto')
 subdir('pg_freespacemap')
 subdir('pg_logicalinspect')
+subdir('pg_overexplain')
 subdir('pg_prewarm')
 subdir('pgrowlocks')
 subdir('pg_stat_statements')
diff --git a/contrib/pg_overexplain/.gitignore b/contrib/pg_overexplain/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/contrib/pg_overexplain/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_overexplain/Makefile b/contrib/pg_overexplain/Makefile
new file mode 100644
index 00000000000..f1c39ecebc1
--- /dev/null
+++ b/contrib/pg_overexplain/Makefile
@@ -0,0 +1,21 @@
+# contrib/pg_overexplain/Makefile
+
+MODULE_big = pg_overexplain
+OBJS = \
+	$(WIN32RES) \
+	pg_overexplain.o
+
+PGFILEDESC = "pg_overexplain - allow EXPLAIN to dump even more details"
+
+REGRESS = pg_overexplain
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_overexplain
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_overexplain/expected/pg_overexplain.out b/contrib/pg_overexplain/expected/pg_overexplain.out
new file mode 100644
index 00000000000..122f1e5da73
--- /dev/null
+++ b/contrib/pg_overexplain/expected/pg_overexplain.out
@@ -0,0 +1,483 @@
+-- These tests display internal details that would not be stable under
+-- debug_parallel_query, so make sure that option is disabled.
+SET debug_parallel_query = off;
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debug"
+LINE 1: EXPLAIN (DEBUG) SELECT 1;
+                 ^
+EXPLAIN (RANGE_TABLE) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "range_table"
+LINE 1: EXPLAIN (RANGE_TABLE) SELECT 1;
+                 ^
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+ERROR:  unrecognized EXPLAIN option "debuff"
+LINE 1: EXPLAIN (DEBUFF) SELECT 1;
+                 ^
+EXPLAIN (DEBUG) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: none
+   Executor Parameter Types: none
+   Parse Location: 16 for 8 bytes
+(11 rows)
+
+EXPLAIN (RANGE_TABLE) SELECT 1;
+                QUERY PLAN                
+------------------------------------------
+ Result  (cost=0.00..0.01 rows=1 width=4)
+ RTI 1 (result):
+   Eref: "*RESULT*" ()
+(3 rows)
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Append
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+               Append RTIs: 1
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     Scan RTI: 3
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled Nodes: 0
+                     Parallel Safe: true
+                     Plan Node ID: 4
+                     Scan RTI: 4
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (group):
+   Eref: "*GROUP*" (genus)
+ RTI 3 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: brassica
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ RTI 4 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 3 4
+(53 rows)
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                           explain_filter                            
+---------------------------------------------------------------------
+ <explain xmlns="http://www.postgresql.org/2009/explain">           +
+   <Query>                                                          +
+     <Plan>                                                         +
+       <Node-Type>Aggregate</Node-Type>                             +
+       <Strategy>Sorted</Strategy>                                  +
+       <Partial-Mode>Simple</Partial-Mode>                          +
+       <Parallel-Aware>false</Parallel-Aware>                       +
+       <Async-Capable>false</Async-Capable>                         +
+       <Disabled>false</Disabled>                                   +
+       <Group-Key>                                                  +
+         <Item>vegetables.genus</Item>                              +
+       </Group-Key>                                                 +
+       <Disabled-Nodes>0</Disabled-Nodes>                           +
+       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Plan-Node-ID>0</Plan-Node-ID>                               +
+       <extParam>none</extParam>                                    +
+       <allParam>none</allParam>                                    +
+       <Plans>                                                      +
+         <Plan>                                                     +
+           <Node-Type>Sort</Node-Type>                              +
+           <Parent-Relationship>Outer</Parent-Relationship>         +
+           <Parallel-Aware>false</Parallel-Aware>                   +
+           <Async-Capable>false</Async-Capable>                     +
+           <Disabled>false</Disabled>                               +
+           <Sort-Key>                                               +
+             <Item>vegetables.genus</Item>                          +
+             <Item>vegetables.name</Item>                           +
+           </Sort-Key>                                              +
+           <Disabled-Nodes>0</Disabled-Nodes>                       +
+           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Plan-Node-ID>1</Plan-Node-ID>                           +
+           <extParam>none</extParam>                                +
+           <allParam>none</allParam>                                +
+           <Plans>                                                  +
+             <Plan>                                                 +
+               <Node-Type>Append</Node-Type>                        +
+               <Parent-Relationship>Outer</Parent-Relationship>     +
+               <Parallel-Aware>false</Parallel-Aware>               +
+               <Async-Capable>false</Async-Capable>                 +
+               <Disabled>false</Disabled>                           +
+               <Disabled-Nodes>0</Disabled-Nodes>                   +
+               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Plan-Node-ID>2</Plan-Node-ID>                       +
+               <extParam>none</extParam>                            +
+               <allParam>none</allParam>                            +
+               <Append-RTIs>1</Append-RTIs>                         +
+               <Subplans-Removed>0</Subplans-Removed>               +
+               <Plans>                                              +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>brassica</Relation-Name>          +
+                   <Alias>vegetables_1</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>3</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>3</Scan-RTI>                           +
+                 </Plan>                                            +
+                 <Plan>                                             +
+                   <Node-Type>Seq Scan</Node-Type>                  +
+                   <Parent-Relationship>Member</Parent-Relationship>+
+                   <Parallel-Aware>false</Parallel-Aware>           +
+                   <Async-Capable>false</Async-Capable>             +
+                   <Relation-Name>daucus</Relation-Name>            +
+                   <Alias>vegetables_2</Alias>                      +
+                   <Disabled>false</Disabled>                       +
+                   <Disabled-Nodes>0</Disabled-Nodes>               +
+                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Plan-Node-ID>4</Plan-Node-ID>                   +
+                   <extParam>none</extParam>                        +
+                   <allParam>none</allParam>                        +
+                   <Scan-RTI>4</Scan-RTI>                           +
+                 </Plan>                                            +
+               </Plans>                                             +
+             </Plan>                                                +
+           </Plans>                                                 +
+         </Plan>                                                    +
+       </Plans>                                                     +
+     </Plan>                                                        +
+     <PlannedStmt>                                                  +
+       <Command-Type>select</Command-Type>                          +
+       <Flags>canSetTag</Flags>                                     +
+       <Subplans-Needing-Rewind>none</Subplans-Needing-Rewind>      +
+       <Relation-OIDs>NNN...</Relation-OIDs>                        +
+       <Executor-Parameter-Types>none</Executor-Parameter-Types>    +
+       <Parse-Location>0 to end</Parse-Location>                    +
+     </PlannedStmt>                                                 +
+     <Range-Table>                                                  +
+       <Range-Table-Entry>                                          +
+         <RTI>1</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>true</Inherited>                                +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>vegetables</Relation>                            +
+         <Relation-Kind>parititioned_table</Relation-Kind>          +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Permission-Info-Index>1</Permission-Info-Index>           +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>2</RTI>                                               +
+         <Kind>group</Kind>                                         +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>false</In-From-Clause>                     +
+         <Eref>"*GROUP*" (genus)</Eref>                             +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>3</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>brassica</Relation>                              +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Range-Table-Entry>                                          +
+         <RTI>4</RTI>                                               +
+         <Kind>relation</Kind>                                      +
+         <Inherited>false</Inherited>                               +
+         <In-From-Clause>true</In-From-Clause>                      +
+         <Alias>vegetables (id, name, genus)</Alias>                +
+         <Eref>vegetables (id, name, genus)</Eref>                  +
+         <Relation>daucus</Relation>                                +
+         <Relation-Kind>relation</Relation-Kind>                    +
+         <Relation-Lock-Mode>AccessShareLock</Relation-Lock-Mode>   +
+         <Security-Barrier>false</Security-Barrier>                 +
+         <Lateral>false</Lateral>                                   +
+       </Range-Table-Entry>                                         +
+       <Unprunable-RTIs>1 3 4</Unprunable-RTIs>                     +
+       <Result-RTIs>none</Result-RTIs>                              +
+     </Range-Table>                                                 +
+   </Query>                                                         +
+ </explain>
+(1 row)
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+                      explain_filter                       
+-----------------------------------------------------------
+ Gather
+   Workers Planned: 1
+   Single Copy: true
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  GroupAggregate
+         Group Key: vegetables.genus
+         Disabled Nodes: 2
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Sort
+               Sort Key: vegetables.genus, vegetables.name
+               Disabled Nodes: 2
+               Parallel Safe: true
+               Plan Node ID: 2
+               ->  Append
+                     Disabled Nodes: 2
+                     Parallel Safe: true
+                     Plan Node ID: 3
+                     ->  Seq Scan on brassica vegetables_1
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 4
+                     ->  Seq Scan on daucus vegetables_2
+                           Disabled: true
+                           Disabled Nodes: 1
+                           Parallel Safe: true
+                           Plan Node ID: 5
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag, parallelModeNeeded
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: none
+   Parse Location: 0 to end
+(37 rows)
+
+RESET debug_parallel_query;
+RESET enable_seqscan;
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+          explain_filter          
+----------------------------------
+ Insert on vegetables
+   Disabled Nodes: 0
+   Parallel Safe: false
+   Plan Node ID: 0
+   ->  Result
+         Disabled Nodes: 0
+         Parallel Safe: false
+         Plan Node ID: 1
+ PlannedStmt:
+   Command Type: insert
+   Flags: hasReturning, canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 0
+   Parse Location: 0 to end
+(15 rows)
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+                                      explain_filter                                      
+------------------------------------------------------------------------------------------
+ Nested Loop (actual rows=8.00 loops=1)
+   Disabled Nodes: 0
+   Parallel Safe: true
+   Plan Node ID: 0
+   ->  Append (actual rows=8.00 loops=1)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 1
+         ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=7.00 loops=1)
+               Index Searches: 1
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 2
+         ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=1.00 loops=1)
+               Index Searches: 1
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 3
+   ->  Append (actual rows=1.00 loops=8)
+         Disabled Nodes: 0
+         Parallel Safe: true
+         Plan Node ID: 4
+         extParam: 0
+         allParam: 0
+         ->  Index Scan using brassica_id_idx on brassica v2_1 (actual rows=0.88 loops=8)
+               Index Cond: (id = v1.id)
+               Index Searches: 8
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 5
+               extParam: 0
+               allParam: 0
+         ->  Index Scan using daucus_id_idx on daucus v2_2 (actual rows=0.12 loops=8)
+               Index Cond: (id = v1.id)
+               Index Searches: 8
+               Disabled Nodes: 0
+               Parallel Safe: true
+               Plan Node ID: 6
+               extParam: 0
+               allParam: 0
+ PlannedStmt:
+   Command Type: select
+   Flags: canSetTag
+   Subplans Needing Rewind: none
+   Relation OIDs: NNN...
+   Executor Parameter Types: 23
+   Parse Location: 75 for 62 bytes
+(47 rows)
+
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+                  QUERY PLAN                  
+----------------------------------------------
+ Seq Scan on daucus vegetables
+   Filter: (genus = 'daucus'::text)
+   Scan RTI: 2
+ RTI 1 (relation, inherited, in-from-clause):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: AccessShareLock
+   Permission Info Index: 1
+ RTI 2 (relation, in-from-clause):
+   Alias: vegetables (id, name, genus)
+   Eref: vegetables (id, name, genus)
+   Relation: daucus
+   Relation Kind: relation
+   Relation Lock Mode: AccessShareLock
+ Unprunable RTIs: 1 2
+(16 rows)
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
+               QUERY PLAN               
+----------------------------------------
+ Insert on vegetables
+   Nominal RTI: 1
+   Exclude Relation RTI: 0
+   ->  Result
+ RTI 1 (relation):
+   Eref: vegetables (id, name, genus)
+   Relation: vegetables
+   Relation Kind: parititioned_table
+   Relation Lock Mode: RowExclusiveLock
+   Permission Info Index: 1
+ RTI 2 (result):
+   Eref: "*RESULT*" ()
+ Unprunable RTIs: 1
+ Result RTIs: 1
+(14 rows)
+
diff --git a/contrib/pg_overexplain/meson.build b/contrib/pg_overexplain/meson.build
new file mode 100644
index 00000000000..6f52d1e51bc
--- /dev/null
+++ b/contrib/pg_overexplain/meson.build
@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2025, PostgreSQL Global Development Group
+
+pg_overexplain_sources = files(
+  'pg_overexplain.c',
+)
+
+if host_system == 'windows'
+  pg_overexplain_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_overexplain',
+    '--FILEDESC', 'pg_overexplain - allow EXPLAIN to dump even more details',])
+endif
+
+pg_overexplain = shared_module('pg_overexplain',
+  pg_overexplain_sources,
+  kwargs: contrib_mod_args,
+)
+contrib_targets += pg_overexplain
+
+tests += {
+  'name': 'pg_overexplain',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_overexplain',
+    ],
+  },
+}
diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
new file mode 100644
index 00000000000..4554c3abbbf
--- /dev/null
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -0,0 +1,763 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_overexplain.c
+ *	  allow EXPLAIN to dump even more details
+ *
+ * Copyright (c) 2016-2025, PostgreSQL Global Development Group
+ *
+ *	  contrib/pg_overexplain/pg_overexplain.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "commands/explain.h"
+#include "commands/explain_format.h"
+#include "commands/explain_state.h"
+#include "fmgr.h"
+#include "parser/parsetree.h"
+#include "storage/lock.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct
+{
+	bool		debug;
+	bool		range_table;
+} overexplain_options;
+
+static overexplain_options *overexplain_ensure_options(ExplainState *es);
+static void overexplain_debug_handler(ExplainState *es, DefElem *opt,
+									  ParseState *pstate);
+static void overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+											ParseState *pstate);
+static void overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+									  const char *relationship,
+									  const char *plan_name,
+									  ExplainState *es);
+static void overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+									  IntoClause *into,
+									  ExplainState *es,
+									  const char *queryString,
+									  ParamListInfo params,
+									  QueryEnvironment *queryEnv);
+static void overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es);
+static void overexplain_range_table(PlannedStmt *plannedstmt,
+									ExplainState *es);
+static void overexplain_alias(const char *qlabel, Alias *alias,
+							  ExplainState *es);
+static void overexplain_bitmapset(const char *qlabel, Bitmapset *bms,
+								  ExplainState *es);
+static void overexplain_intlist(const char *qlabel, List *intlist,
+								ExplainState *es);
+
+static int	es_extension_id;
+static explain_per_node_hook_type prev_explain_per_node_hook;
+static explain_per_plan_hook_type prev_explain_per_plan_hook;
+
+/*
+ * Initialization we do when this module is loaded.
+ */
+void
+_PG_init(void)
+{
+	/* Get an ID that we can use to cache data in an ExplainState. */
+	es_extension_id = GetExplainExtensionId("pg_overexplain");
+
+	/* Register the new EXPLAIN options implemented by this module. */
+	RegisterExtensionExplainOption("debug", overexplain_debug_handler);
+	RegisterExtensionExplainOption("range_table",
+								   overexplain_range_table_handler);
+
+	/* Use the per-node and per-plan hooks to make our options do something. */
+	prev_explain_per_node_hook = explain_per_node_hook;
+	explain_per_node_hook = overexplain_per_node_hook;
+	prev_explain_per_plan_hook = explain_per_plan_hook;
+	explain_per_plan_hook = overexplain_per_plan_hook;
+}
+
+/*
+ * Get the overexplain_options structure from an ExplainState; if there is
+ * none, create one, attach it to the ExplainState, and return it.
+ */
+static overexplain_options *
+overexplain_ensure_options(ExplainState *es)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+
+	if (options == NULL)
+	{
+		options = palloc0(sizeof(overexplain_options));
+		SetExplainExtensionState(es, es_extension_id, options);
+	}
+
+	return options;
+}
+
+/*
+ * Parse handler for EXPLAIN (DEBUG).
+ */
+static void
+overexplain_debug_handler(ExplainState *es, DefElem *opt, ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->debug = defGetBoolean(opt);
+}
+
+/*
+ * Parse handler for EXPLAIN (RANGE_TABLE).
+ */
+static void
+overexplain_range_table_handler(ExplainState *es, DefElem *opt,
+								ParseState *pstate)
+{
+	overexplain_options *options = overexplain_ensure_options(es);
+
+	options->range_table = defGetBoolean(opt);
+}
+
+/*
+ * Print out additional per-node information as appropriate. If the user didn't
+ * specify any of the options we support, do nothing; else, print whatever is
+ * relevant to the specified options.
+ */
+static void
+overexplain_per_node_hook(PlanState *planstate, List *ancestors,
+						  const char *relationship, const char *plan_name,
+						  ExplainState *es)
+{
+	overexplain_options *options;
+	Plan	   *plan = planstate->plan;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	/*
+	 * If the "debug" option was given, display miscellaneous fields from the
+	 * "Plan" node that would not otherwise be displayed.
+	 */
+	if (options->debug)
+	{
+		/*
+		 * Normal EXPLAIN will display "Disabled: true" if the node is
+		 * disabled; but that is based on noticing that plan->disabled_nodes
+		 * is higher than the sum of its children; here, we display the raw
+		 * value, for debugging purposes.
+		 */
+		ExplainPropertyInteger("Disabled Nodes", NULL, plan->disabled_nodes,
+							   es);
+
+		/*
+		 * Normal EXPLAIN will display the parallel_aware flag; here, we show
+		 * the parallel_safe flag as well.
+		 */
+		ExplainPropertyBool("Parallel Safe", plan->parallel_safe, es);
+
+		/*
+		 * The plan node ID isn't normally displayed, since it is only useful
+		 * for debugging.
+		 */
+		ExplainPropertyInteger("Plan Node ID", NULL, plan->plan_node_id, es);
+
+		/*
+		 * It is difficult to explain what extParam and allParam mean in plain
+		 * language, so we simply display these fields labelled with the
+		 * structure member name. For compactness, the text format omits the
+		 * display of this information when the bitmapset is empty.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->extParam))
+			overexplain_bitmapset("extParam", plan->extParam, es);
+		if (es->format != EXPLAIN_FORMAT_TEXT || !bms_is_empty(plan->allParam))
+			overexplain_bitmapset("allParam", plan->allParam, es);
+	}
+
+	/*
+	 * If the "range_table" option was specified, display information about
+	 * the range table indexes for this node.
+	 */
+	if (options->range_table)
+	{
+		switch (nodeTag(plan))
+		{
+			case T_SeqScan:
+			case T_SampleScan:
+			case T_IndexScan:
+			case T_IndexOnlyScan:
+			case T_BitmapHeapScan:
+			case T_TidScan:
+			case T_TidRangeScan:
+			case T_SubqueryScan:
+			case T_FunctionScan:
+			case T_TableFuncScan:
+			case T_ValuesScan:
+			case T_CteScan:
+			case T_NamedTuplestoreScan:
+			case T_WorkTableScan:
+				ExplainPropertyInteger("Scan RTI", NULL,
+									   ((Scan *) plan)->scanrelid, es);
+				break;
+			case T_ForeignScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((ForeignScan *) plan)->fs_base_relids,
+									  es);
+				break;
+			case T_CustomScan:
+				overexplain_bitmapset("Scan RTIs",
+									  ((CustomScan *) plan)->custom_relids,
+									  es);
+				break;
+			case T_ModifyTable:
+				ExplainPropertyInteger("Nominal RTI", NULL,
+									   ((ModifyTable *) plan)->nominalRelation, es);
+				ExplainPropertyInteger("Exclude Relation RTI", NULL,
+									   ((ModifyTable *) plan)->exclRelRTI, es);
+				break;
+			case T_Append:
+				overexplain_bitmapset("Append RTIs",
+									  ((Append *) plan)->apprelids,
+									  es);
+				break;
+			case T_MergeAppend:
+				overexplain_bitmapset("Append RTIs",
+									  ((MergeAppend *) plan)->apprelids,
+									  es);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+/*
+ * Print out additional per-query information as appropriate. Here again, if
+ * the user didn't specify any of the options implemented by this module, do
+ * nothing; otherwise, call the appropriate function for each specified
+ * option.
+ */
+static void
+overexplain_per_plan_hook(PlannedStmt *plannedstmt,
+						  IntoClause *into,
+						  ExplainState *es,
+						  const char *queryString,
+						  ParamListInfo params,
+						  QueryEnvironment *queryEnv)
+{
+	overexplain_options *options;
+
+	options = GetExplainExtensionState(es, es_extension_id);
+	if (options == NULL)
+		return;
+
+	if (options->debug)
+		overexplain_debug(plannedstmt, es);
+
+	if (options->range_table)
+		overexplain_range_table(plannedstmt, es);
+}
+
+/*
+ * Print out various details from the PlannedStmt that wouldn't otherwise
+ * be displayed.
+ *
+ * We don't try to print everything here. Information that would be displyed
+ * anyway doesn't need to be printed again here, and things with lots of
+ * substructure probably should be printed via separate options, or not at all.
+ */
+static void
+overexplain_debug(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	char	   *commandType = NULL;
+	StringInfoData flags;
+
+	/* Even in text mode, we want to set this output apart as its own group. */
+	ExplainOpenGroup("PlannedStmt", "PlannedStmt", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "PlannedStmt:\n");
+		es->indent++;
+	}
+
+	/* Print the command type. */
+	switch (plannedstmt->commandType)
+	{
+		case CMD_UNKNOWN:
+			commandType = "unknown";
+			break;
+		case CMD_SELECT:
+			commandType = "select";
+			break;
+		case CMD_UPDATE:
+			commandType = "update";
+			break;
+		case CMD_INSERT:
+			commandType = "insert";
+			break;
+		case CMD_DELETE:
+			commandType = "delete";
+			break;
+		case CMD_MERGE:
+			commandType = "merge";
+			break;
+		case CMD_UTILITY:
+			commandType = "utility";
+			break;
+		case CMD_NOTHING:
+			commandType = "nothing";
+			break;
+	}
+	ExplainPropertyText("Command Type", commandType, es);
+
+	/* Print various properties as a comma-separated list of flags. */
+	initStringInfo(&flags);
+	if (plannedstmt->hasReturning)
+		appendStringInfo(&flags, ", hasReturning");
+	if (plannedstmt->hasModifyingCTE)
+		appendStringInfo(&flags, ", hasModifyingCTE");
+	if (plannedstmt->canSetTag)
+		appendStringInfo(&flags, ", canSetTag");
+	if (plannedstmt->transientPlan)
+		appendStringInfo(&flags, ", transientPlan");
+	if (plannedstmt->dependsOnRole)
+		appendStringInfo(&flags, ", dependsOnRole");
+	if (plannedstmt->parallelModeNeeded)
+		appendStringInfo(&flags, ", parallelModeNeeded");
+	if (flags.len == 0)
+		appendStringInfo(&flags, ", none");
+	ExplainPropertyText("Flags", flags.data + 2, es);
+
+	/* Various lists of integers. */
+	overexplain_bitmapset("Subplans Needing Rewind",
+						  plannedstmt->rewindPlanIDs, es);
+	overexplain_intlist("Relation OIDs",
+						plannedstmt->relationOids, es);
+	overexplain_intlist("Executor Parameter Types",
+						plannedstmt->paramExecTypes, es);
+
+	/*
+	 * Print the statement location. (If desired, we could alternatively print
+	 * stmt_location and stmt_len as two separate fields.)
+	 */
+	if (plannedstmt->stmt_location == -1)
+		ExplainPropertyText("Parse Location", "Unknown", es);
+	else if (plannedstmt->stmt_len == 0)
+		ExplainPropertyText("Parse Location",
+							psprintf("%d to end", plannedstmt->stmt_location),
+							es);
+	else
+		ExplainPropertyText("Parse Location",
+							psprintf("%d for %d bytes",
+									 plannedstmt->stmt_location,
+									 plannedstmt->stmt_len),
+							es);
+
+	/* Done with this group. */
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+		es->indent--;
+	ExplainCloseGroup("PlannedStmt", "PlannedStmt", true, es);
+}
+
+/*
+ * Provide detailed information about the contents of the PlannedStmt's
+ * range table.
+ */
+static void
+overexplain_range_table(PlannedStmt *plannedstmt, ExplainState *es)
+{
+	Index		rti;
+
+	/* Open group, one entry per RangeTblEntry */
+	ExplainOpenGroup("Range Table", "Range Table", false, es);
+
+	/* Iterate over the range table */
+	for (rti = 1; rti <= list_length(plannedstmt->rtable); ++rti)
+	{
+		RangeTblEntry *rte = rt_fetch(rti, plannedstmt->rtable);
+		char	   *kind = NULL;
+		char	   *relkind;
+
+		/* NULL entries are possible; skip them */
+		if (rte == NULL)
+			continue;
+
+		/* Translate rtekind to a string */
+		switch (rte->rtekind)
+		{
+			case RTE_RELATION:
+				kind = "relation";
+				break;
+			case RTE_SUBQUERY:
+				kind = "subquery";
+				break;
+			case RTE_JOIN:
+				kind = "join";
+				break;
+			case RTE_FUNCTION:
+				kind = "function";
+				break;
+			case RTE_TABLEFUNC:
+				kind = "tablefunc";
+				break;
+			case RTE_VALUES:
+				kind = "values";
+				break;
+			case RTE_CTE:
+				kind = "cte";
+				break;
+			case RTE_NAMEDTUPLESTORE:
+				kind = "namedtuplestore";
+				break;
+			case RTE_RESULT:
+				kind = "result";
+				break;
+			case RTE_GROUP:
+				kind = "group";
+				break;
+		}
+
+		/* Begin group for this specific RTE */
+		ExplainOpenGroup("Range Table Entry", NULL, true, es);
+
+		/*
+		 * In text format, the summary line displays the range table index and
+		 * rtekind, plus indications if rte->inh and/or rte->inFromCl are set.
+		 * In other formats, we display those as separate properties.
+		 */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str, "RTI %u (%s%s%s):\n", rti, kind,
+							 rte->inh ? ", inherited" : "",
+							 rte->inFromCl ? ", in-from-clause" : "");
+			es->indent++;
+		}
+		else
+		{
+			ExplainPropertyUInteger("RTI", NULL, rti, es);
+			ExplainPropertyText("Kind", kind, es);
+			ExplainPropertyBool("Inherited", rte->inh, es);
+			ExplainPropertyBool("In From Clause", rte->inFromCl, es);
+		}
+
+		/* rte->alias is optional; rte->eref is requested */
+		if (rte->alias != NULL)
+			overexplain_alias("Alias", rte->alias, es);
+		overexplain_alias("Eref", rte->eref, es);
+
+		/*
+		 * We adhere to the usual EXPLAIN convention that schema names are
+		 * displayed only in verbose mode, and we emit nothing if there is no
+		 * relation OID.
+		 */
+		if (rte->relid != 0)
+		{
+			const char *relname;
+			const char *qualname;
+
+			relname = quote_identifier(get_rel_name(rte->relid));
+
+			if (es->verbose)
+			{
+				Oid			nspoid = get_rel_namespace(rte->relid);
+				char	   *nspname;
+
+				nspname = get_namespace_name_or_temp(nspoid);
+				qualname = psprintf("%s.%s", quote_identifier(nspname),
+									relname);
+			}
+			else
+				qualname = relname;
+
+			ExplainPropertyText("Relation", qualname, es);
+		}
+
+		/* Translate relkind, if any, to a string */
+		switch (rte->relkind)
+		{
+			case RELKIND_RELATION:
+				relkind = "relation";
+				break;
+			case RELKIND_INDEX:
+				relkind = "index";
+				break;
+			case RELKIND_SEQUENCE:
+				relkind = "sequence";
+				break;
+			case RELKIND_TOASTVALUE:
+				relkind = "toastvalue";
+				break;
+			case RELKIND_VIEW:
+				relkind = "view";
+				break;
+			case RELKIND_MATVIEW:
+				relkind = "matview";
+				break;
+			case RELKIND_COMPOSITE_TYPE:
+				relkind = "composite_type";
+				break;
+			case RELKIND_FOREIGN_TABLE:
+				relkind = "foreign_table";
+				break;
+			case RELKIND_PARTITIONED_TABLE:
+				relkind = "parititioned_table";
+				break;
+			case RELKIND_PARTITIONED_INDEX:
+				relkind = "parititioned_index";
+				break;
+			case '\0':
+				relkind = NULL;
+				break;
+			default:
+				relkind = psprintf("%c", rte->relkind);
+				break;
+		}
+
+		/* If there is a relkind, show it */
+		if (relkind != NULL)
+			ExplainPropertyText("Relation Kind", relkind, es);
+
+		/* If there is a lock mode, show it */
+		if (rte->rellockmode != 0)
+			ExplainPropertyText("Relation Lock Mode",
+								GetLockmodeName(DEFAULT_LOCKMETHOD,
+												rte->rellockmode), es);
+
+		/*
+		 * If there is a perminfoindex, show it. We don't try to display
+		 * information from the RTEPermissionInfo node here because they are
+		 * just indexes plannedstmt->permInfos which could be separately
+		 * dumped if someone wants to add EXPLAIN (PERMISSIONS) or similar.
+		 */
+		if (rte->perminfoindex != 0)
+			ExplainPropertyInteger("Permission Info Index", NULL,
+								   rte->perminfoindex, es);
+
+		/*
+		 * add_rte_to_flat_rtable will clear rte->tablesample and
+		 * rte->subquery in the finished plan, so skip those fields.
+		 *
+		 * However, the security_barrier flag is not shown by the core code,
+		 * so let's print it here.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->security_barrier)
+			ExplainPropertyBool("Security Barrier", rte->security_barrier, es);
+
+		/*
+		 * If this is a join, print out the fields that are specifically valid
+		 * for joins.
+		 */
+		if (rte->rtekind == RTE_JOIN)
+		{
+			char	   *jointype;
+
+			switch (rte->jointype)
+			{
+				case JOIN_INNER:
+					jointype = "Inner";
+					break;
+				case JOIN_LEFT:
+					jointype = "Left";
+					break;
+				case JOIN_FULL:
+					jointype = "Full";
+					break;
+				case JOIN_RIGHT:
+					jointype = "Right";
+					break;
+				case JOIN_SEMI:
+					jointype = "Semi";
+					break;
+				case JOIN_ANTI:
+					jointype = "Anti";
+					break;
+				case JOIN_RIGHT_SEMI:
+					jointype = "Right Semi";
+					break;
+				case JOIN_RIGHT_ANTI:
+					jointype = "Right Anti";
+					break;
+				default:
+					jointype = "???";
+					break;
+			}
+
+			/* Join type */
+			ExplainPropertyText("Join Type", jointype, es);
+
+			/* # of JOIN USING columns */
+			if (es->format != EXPLAIN_FORMAT_TEXT || rte->joinmergedcols != 0)
+				ExplainPropertyInteger("JOIN USING Columns", NULL,
+									   rte->joinmergedcols, es);
+
+			/*
+			 * add_rte_to_flat_rtable will clear joinaliasvars, joinleftcols,
+			 * joinrightcols, and join_using_alias here, so skip those fields.
+			 */
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear functions, tablefunc, and
+		 * values_lists, but we can display funcordinality.
+		 */
+		if (rte->rtekind == RTE_FUNCTION)
+			ExplainPropertyBool("WITH ORDINALITY", rte->funcordinality, es);
+
+		/*
+		 * If this is a CTE, print out CTE-related properties.
+		 */
+		if (rte->rtekind == RTE_CTE)
+		{
+			ExplainPropertyText("CTE Name", rte->ctename, es);
+			ExplainPropertyUInteger("CTE Levels Up", NULL, rte->ctelevelsup,
+									es);
+			ExplainPropertyBool("CTE Self-Reference", rte->self_reference, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear coltypes, coltypemods, and
+		 * colcollations, so skip those fields.
+		 *
+		 * If this is an ephemeral named relation, print out ENR-related
+		 * properties.
+		 */
+		if (rte->rtekind == RTE_NAMEDTUPLESTORE)
+		{
+			ExplainPropertyText("ENR Name", rte->enrname, es);
+			ExplainPropertyFloat("ENR Tuples", NULL, rte->enrtuples, 0, es);
+		}
+
+		/*
+		 * add_rte_to_flat_rtable will clear groupexprs and securityQuals, so
+		 * skip that field. We have handled inFromCl above, so the only thing
+		 * left to handle here is rte->lateral.
+		 */
+		if (es->format != EXPLAIN_FORMAT_TEXT || rte->lateral)
+			ExplainPropertyBool("Lateral", rte->lateral, es);
+
+		/* Done with this RTE */
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+		ExplainCloseGroup("Range Table Entry", NULL, true, es);
+	}
+
+	/* Print PlannedStmt fields that contain RTIs. */
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		!bms_is_empty(plannedstmt->unprunableRelids))
+		overexplain_bitmapset("Unprunable RTIs", plannedstmt->unprunableRelids,
+							  es);
+	if (es->format != EXPLAIN_FORMAT_TEXT ||
+		plannedstmt->resultRelations != NIL)
+		overexplain_intlist("Result RTIs", plannedstmt->resultRelations, es);
+
+	/* Close group, we're all done */
+	ExplainCloseGroup("Range Table", "Range Table", false, es);
+}
+
+/*
+ * Emit a text property describing the contents of an Alias.
+ *
+ * Column lists can be quite long here, so perhaps we should have an option
+ * to limit the display length by # of columsn or # of characters, but for
+ * now, just display everything.
+ */
+static void
+overexplain_alias(const char *qlabel, Alias *alias, ExplainState *es)
+{
+	StringInfoData buf;
+	bool		first = true;
+
+	Assert(alias != NULL);
+
+	initStringInfo(&buf);
+	appendStringInfo(&buf, "%s (", quote_identifier(alias->aliasname));
+
+	foreach_node(String, cn, alias->colnames)
+	{
+		appendStringInfo(&buf, "%s%s",
+						 first ? "" : ", ",
+						 quote_identifier(cn->sval));
+		first = false;
+	}
+
+	appendStringInfoChar(&buf, ')');
+	ExplainPropertyText(qlabel, buf.data, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a bitmapset -- either a
+ * space-separated list of integer members, or the word "none" if the bitmapset
+ * is empty.
+ */
+static void
+overexplain_bitmapset(const char *qlabel, Bitmapset *bms, ExplainState *es)
+{
+	int			x = -1;
+
+	StringInfoData buf;
+
+	if (bms_is_empty(bms))
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	initStringInfo(&buf);
+	while ((x = bms_next_member(bms, x)) >= 0)
+		appendStringInfo(&buf, " %d", x);
+	Assert(buf.data[0] == ' ');
+	ExplainPropertyText(qlabel, buf.data + 1, es);
+	pfree(buf.data);
+}
+
+/*
+ * Emit a text property describing the contents of a list of integers, OIDs,
+ * or XIDs -- either a space-separated list of integer members, or the word
+ * "none" if the list is empty.
+ */
+static void
+overexplain_intlist(const char *qlabel, List *list, ExplainState *es)
+{
+	StringInfoData buf;
+
+	initStringInfo(&buf);
+
+	if (list == NIL)
+	{
+		ExplainPropertyText(qlabel, "none", es);
+		return;
+	}
+
+	if (IsA(list, IntList))
+	{
+		foreach_int(i, list)
+			appendStringInfo(&buf, " %d", i);
+	}
+	else if (IsA(list, OidList))
+	{
+		foreach_oid(o, list)
+			appendStringInfo(&buf, " %u", o);
+	}
+	else if (IsA(list, XidList))
+	{
+		foreach_xid(x, list)
+			appendStringInfo(&buf, " %u", x);
+	}
+	else
+	{
+		appendStringInfo(&buf, " not an integer list");
+		Assert(false);
+	}
+
+	if (buf.len > 0)
+		ExplainPropertyText(qlabel, buf.data + 1, es);
+
+	pfree(buf.data);
+}
diff --git a/contrib/pg_overexplain/sql/pg_overexplain.sql b/contrib/pg_overexplain/sql/pg_overexplain.sql
new file mode 100644
index 00000000000..ae9082b1e85
--- /dev/null
+++ b/contrib/pg_overexplain/sql/pg_overexplain.sql
@@ -0,0 +1,105 @@
+-- These tests display internal details that would not be stable under
+-- debug_parallel_query, so make sure that option is disabled.
+SET debug_parallel_query = off;
+
+-- These options do not exist, so these queries should all fail.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Load the module that creates the options.
+LOAD 'pg_overexplain';
+
+-- The first option still does not exist, but the others do.
+EXPLAIN (DEBUFF) SELECT 1;
+EXPLAIN (DEBUG) SELECT 1;
+EXPLAIN (RANGE_TABLE) SELECT 1;
+
+-- Create a partitioned table.
+CREATE TABLE vegetables (id serial, name text, genus text)
+PARTITION BY LIST (genus);
+CREATE TABLE daucus PARTITION OF vegetables FOR VALUES IN ('daucus');
+CREATE TABLE brassica PARTITION OF vegetables FOR VALUES IN ('brassica');
+INSERT INTO vegetables (name, genus)
+	VALUES ('carrot', 'daucus'), ('bok choy', 'brassica'),
+		   ('brocooli', 'brassica'), ('cauliflower', 'brassica'),
+		   ('cabbage', 'brassica'), ('kohlrabi', 'brassica'),
+		   ('rutabaga', 'brassica'), ('turnip', 'brassica');
+VACUUM ANALYZE vegetables;
+
+-- We filter relation OIDs out of the test output in order to avoid
+-- test instability. This is currently only needed for EXPLAIN (DEBUG), not
+-- EXPLAIN (RANGE_TABLE).
+CREATE FUNCTION explain_filter(text) RETURNS SETOF text
+LANGUAGE plpgsql AS
+$$
+DECLARE
+    ln text;
+BEGIN
+    FOR ln IN EXECUTE $1
+	LOOP
+		ln := regexp_replace(ln, 'Relation OIDs:( \m\d+\M)+',
+								 'Relation OIDs: NNN...', 'g');
+		ln := regexp_replace(ln, '<Relation-OIDs>( ?\m\d+\M)+</Relation-OIDs>',
+								 '<Relation-OIDs>NNN...</Relation-OIDs>', 'g');
+		RETURN NEXT ln;
+	END LOOP;
+END;
+$$;
+
+-- Test with both options together and an aggregate.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test a different output format.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, RANGE_TABLE, FORMAT XML, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+
+-- Test just the DEBUG option. Verify that it shows information about
+-- disabled nodes, parallel safety, and the parallelModeNeeded flag.
+SET enable_seqscan = false;
+SET debug_parallel_query = true;
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
+$$);
+RESET debug_parallel_query;
+RESET enable_seqscan;
+
+-- Test the DEBUG option with a non-SELECT query, and also verify that the
+-- hasReturning flag is shown.
+SELECT explain_filter($$
+EXPLAIN (DEBUG, COSTS OFF)
+INSERT INTO vegetables (name, genus)
+	VALUES ('Brotero''s carrot', 'brassica') RETURNING id
+$$);
+
+-- Create an index, and then attempt to force a nested loop with inner index
+-- scan so that we can see parameter-related information. Also, let's try
+-- actually running the query, but try to suppress potentially variable output.
+CREATE INDEX ON vegetables (id);
+ANALYZE vegetables;
+SET enable_hashjoin = false;
+SET enable_material = false;
+SET enable_mergejoin = false;
+SET enable_seqscan = false;
+SELECT explain_filter($$
+EXPLAIN (BUFFERS OFF, COSTS OFF, SUMMARY OFF, TIMING OFF, ANALYZE, DEBUG)
+SELECT * FROM vegetables v1, vegetables v2 WHERE v1.id = v2.id;
+$$);
+RESET enable_hashjoin;
+RESET enable_material;
+RESET enable_mergejoin;
+RESET enable_seqscan;
+
+-- Test the RANGE_TABLE option with a case that allows partition pruning.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+SELECT * FROM vegetables WHERE genus = 'daucus';
+
+-- Also test a case that involves a write.
+EXPLAIN (RANGE_TABLE, COSTS OFF)
+INSERT INTO vegetables (name, genus) VALUES ('broccoflower', 'brassica');
diff --git a/doc/src/sgml/contrib.sgml b/doc/src/sgml/contrib.sgml
index 7c381949a53..24b706b29ad 100644
--- a/doc/src/sgml/contrib.sgml
+++ b/doc/src/sgml/contrib.sgml
@@ -155,6 +155,7 @@ CREATE EXTENSION <replaceable>extension_name</replaceable>;
  &pgcrypto;
  &pgfreespacemap;
  &pglogicalinspect;
+ &pgoverexplain;
  &pgprewarm;
  &pgrowlocks;
  &pgstatstatements;
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml
index 25fb99cee69..fef9584f908 100644
--- a/doc/src/sgml/filelist.sgml
+++ b/doc/src/sgml/filelist.sgml
@@ -145,6 +145,7 @@
 <!ENTITY pgcrypto        SYSTEM "pgcrypto.sgml">
 <!ENTITY pgfreespacemap  SYSTEM "pgfreespacemap.sgml">
 <!ENTITY pglogicalinspect  SYSTEM "pglogicalinspect.sgml">
+<!ENTITY pgoverexplain   SYSTEM "pgoverexplain.sgml">
 <!ENTITY pgprewarm       SYSTEM "pgprewarm.sgml">
 <!ENTITY pgrowlocks      SYSTEM "pgrowlocks.sgml">
 <!ENTITY pgstatstatements SYSTEM "pgstatstatements.sgml">
diff --git a/doc/src/sgml/pgoverexplain.sgml b/doc/src/sgml/pgoverexplain.sgml
new file mode 100644
index 00000000000..102bd275aed
--- /dev/null
+++ b/doc/src/sgml/pgoverexplain.sgml
@@ -0,0 +1,186 @@
+<!-- doc/src/sgml/pgoverexplain.sgml -->
+
+<sect1 id="pgoverexplain" xreflabel="pg_overexplain">
+ <title>pg_overexplain &mdash; allow EXPLAIN to dump even more details</title>
+
+ <indexterm zone="pgoverexplain">
+  <primary>pg_overexplain</primary>
+ </indexterm>
+
+ <para>
+  The <filename>pg_overexplain</filename> extends <command>EXPLAIN</command>
+  with new options that provide additional output. It is mostly intended to
+  assist with debugging of and development of the planner, rather than for
+  general use. Since this module displays internal details of planner data
+  structures, it may be necessary to refer to the source code to make sense
+  of the output. Furthermore, the output is likely to change whenever (and as
+  often as) those data structures change.
+ </para>
+
+ <sect2 id="pgoverexplain-debug">
+  <title>EXPLAIN (DEBUG)</title>
+
+  <para>
+   The <literal>DEBUG</literal> option displays miscellaneous information from
+   the plan tree that is not normally shown because it is not expected to be
+   of general interest. For each individual plan node, it will display the
+   following fields.  See <literal>Plan</literal> in
+   <literal>nodes/plannodes.h</literal> for additional documentation of these
+   fields.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Disabled Nodes</literal>. Normal <command>EXPLAIN</command>
+     determines whether a node is disabled by checking whether the node's
+     count of disabled nodes is larger than the sum of the counts for the
+     underlying nodes. This option shows the raw counter value.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parallel Safe</literal>. Indicates whether it would be safe for
+     a plan tree node to appear beneath a <literal>Gather</literal> or
+     <literal>Gather Merge</literal> node, regardless of whether it is
+     actually below such a node.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Plan Node ID</literal>. An internal ID number that should be
+     unique for every node in the plan tree. It is used to coordinate parallel
+     query activity.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>extParam</literal> and <literal>allParam</literal>. Information
+     about which numbered parameters affect this plan node or its children. In
+     text mode, these fields are only displayed if they are non-empty sets.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   Once per query, the <literal>DEBUG</literal> option will display the
+   following fields. See <literal>PlannedStmt</literal> in
+   <literal>nodes/plannodes.h</literal> for additional detail.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>Command Type</literal>. For example, <literal>select</literal>
+     or <literal>update</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Flags</literal>. A comma-separated list of Boolean structure
+     member names from the <literal>PlannedStmt</literal> that are set to
+     <literal>true</literal>. It covers the following structure members:
+     <literal>hasReturning</literal>, <literal>hasModifyingCTE</literal>,
+     <literal>canSetTag</literal>, <literal>transientPlan</literal>,
+     <literal>dependsOnRole</literal>, <literal>parallelModeNeeded</literal>.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Subplans Needing Rewind</literal>. Integer IDs of subplans that 
+     may need to be rewound by the executor.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Relation OIDs</literal>. OIDs of relations upon which this plan
+     depends.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Executor Parameter Types</literal>. Type OID for each executor parameter
+     (e.g. when a nested loop is chosen and a parameter is used to pass a value down
+     to an inner index scan). Does not include parameters supplied to a prepared
+     statement by the user.
+    </para>
+   </listitem>
+
+   <listitem>
+    <para>
+     <literal>Parse Location</literal>. Location within the query string
+     supplied to the planner where this query's text can be found. May be
+     <literal>Unknown</literal> in some contexts. Otherwise, may be
+     <literal>NNN to end</literal> for some integer <literal>NNN</literal> or
+     <literal>NNN for MMM bytes</literal> for some integers
+     <literal>NNN</literal> and <literal>MMM</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </sect2>
+
+ <sect2 id="pgoverexplain-range-table">
+  <title>EXPLAIN (RANGE_TABLE)</title>
+
+  <para>
+   The <literal>RANGE_TABLE</literal> option displays information from the
+   plan tree specifically concerning the query's range table. Range table
+   entries correspond roughly to items appearing in the query's
+   <literal>FROM</literal> clause, but with numerous exceptions. For example,
+   subqueries that are proved unnecessary may be deleted from the range table
+   entirely, while inheritance expansion adds range table entries for child
+   tables that are not named directly in the query.
+  </para>
+
+  <para>
+   Range table entries are generally referenced within the query plan by a
+   range table index, or RTI. Plan nodes that reference one or more RTIs will
+   be labelled accordingly, using one of the following fields: <literal>Scan
+   RTI</literal>, <literal>Nominal RTI</literal>, <literal>Exclude Relation
+   RTI</literal>, <literal>Append RTIs</literal>.
+  </para>
+
+  <para>
+   In addition, the query as a whole may maintain lists of range table indexes
+   that are needed for various purposes. These lists will be displayed once
+   per query, labelled as appropriate as <literal>Unprunable RTIs</literal> or
+   <literal>Result RTIs</literal>. In text mode, these fields are only
+   displayed if they are non-empty sets.
+  </para>
+
+  <para>
+   Finally, but most importantly, the <literal>RANGE_TABLE</literal> option
+   will display a dump of the query's entire range table. Each range table
+   entry is labelled with the appropriate range table index, the kind of range
+   table entry (e.g.  <literal>relation</literal>,
+   <literal>subquery</literal>, or <literal>join</literal>), followed by the
+   contents of various range table entry fields that are not normally part of
+   <literal>EXPLAIN</literal> output. Some of these fields are only displayed
+   for certain kinds of range table entries. For example,
+   <literal>Eref</literal> is displayed for all types of range table entries,
+   but <literal>CTE Name</literal> is displayed only for range table entries
+   of type <literal>cte</literal>.
+  </para>
+
+  <para>
+   For more information about range table entries, see the definition of
+   <literal>RangeTblEntry</literal> in <literal>nodes/plannodes.h</literal>.
+  </para>
+ </sect2>
+
+ <sect2 id="pgoverexplain-author">
+  <title>Author</title>
+
+  <para>
+   Robert Haas <email>rhaas@postgresql.org</email>
+  </para>
+ </sect2>
+
+</sect1>
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index bfa276d2d35..38432f4e27b 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4276,3 +4276,4 @@ z_streamp
 zic_t
 ExplainExtensionOption
 ExplainOptionHandler
+overexplain_options
-- 
2.39.3 (Apple Git-145)

From 03a88d291cfe085bcff10e0595a679bcfcf14fc8 Mon Sep 17 00:00:00 2001
From: "Andrei V. Lepikhov" <lepihov@gmail.com>
Date: Thu, 27 Mar 2025 22:27:33 +0100
Subject: [PATCH v0] Add into pg_overexplain example on a hook call chain
 agreement.

---
 contrib/pg_overexplain/pg_overexplain.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/contrib/pg_overexplain/pg_overexplain.c b/contrib/pg_overexplain/pg_overexplain.c
index 4554c3abbbf..5f623e06019 100644
--- a/contrib/pg_overexplain/pg_overexplain.c
+++ b/contrib/pg_overexplain/pg_overexplain.c
@@ -135,6 +135,10 @@ overexplain_per_node_hook(PlanState *planstate, List *ancestors,
 	overexplain_options *options;
 	Plan	   *plan = planstate->plan;
 
+	if (prev_explain_per_node_hook)
+		(*prev_explain_per_node_hook) (planstate, ancestors, relationship,
+									   plan_name, es);
+
 	options = GetExplainExtensionState(es, es_extension_id);
 	if (options == NULL)
 		return;
@@ -251,6 +255,10 @@ overexplain_per_plan_hook(PlannedStmt *plannedstmt,
 {
 	overexplain_options *options;
 
+	if (prev_explain_per_plan_hook)
+		(*prev_explain_per_plan_hook) (plannedstmt, into, es, queryString,
+									   params, queryEnv);
+
 	options = GetExplainExtensionState(es, es_extension_id);
 	if (options == NULL)
 		return;
-- 
2.39.5