Show various offset arrays for heap WAL records

From 10ec7b3366f7ffdc31295831cb112863446fb578 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Wed, 25 Jan 2023 08:38:38 -0500
Subject: [PATCH v1] Add rmgr_desc utilities

- Begin to standardize format of rmgr_desc output, adding a new
  rmgr_utils file with comments about expected format.
- Add helper which prints arrays in a standard format and use it in
  heapdesc to print out offset arrays, relid arrays, freeze plan arrays,
  and relid arrays
---
 src/backend/access/rmgrdesc/Makefile         |   1 +
 src/backend/access/rmgrdesc/heapdesc.c       | 154 +++++++++++++++----
 src/backend/access/rmgrdesc/meson.build      |   1 +
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  88 +++++++++++
 src/bin/pg_waldump/Makefile                  |   2 +-
 src/include/access/heapam_xlog.h             |   1 +
 src/include/access/rmgrdesc_utils.h          |  33 ++++
 7 files changed, 251 insertions(+), 29 deletions(-)
 create mode 100644 src/backend/access/rmgrdesc/rmgrdesc_utils.c
 create mode 100644 src/include/access/rmgrdesc_utils.h

diff --git a/src/backend/access/rmgrdesc/Makefile b/src/backend/access/rmgrdesc/Makefile
index f88d72fd86..cd95eec37f 100644
--- a/src/backend/access/rmgrdesc/Makefile
+++ b/src/backend/access/rmgrdesc/Makefile
@@ -23,6 +23,7 @@ OBJS = \
 	nbtdesc.o \
 	relmapdesc.o \
 	replorigindesc.o \
+	rmgrdesc_utils.o \
 	seqdesc.o \
 	smgrdesc.o \
 	spgdesc.o \
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e8215..25a663c71b 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -15,22 +15,56 @@
 #include "postgres.h"
 
 #include "access/heapam_xlog.h"
+#include "access/rmgrdesc_utils.h"
+
 
 static void
 out_infobits(StringInfo buf, uint8 infobits)
 {
+	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
+		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
+		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
+		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
+		(infobits & XLHL_KEYS_UPDATED) == 0)
+		return;
+
+	appendStringInfoString(buf, ", infobits: [");
+
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, "IS_MULTI ");
+		appendStringInfoString(buf, " IS_MULTI");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, "LOCK_ONLY ");
+		appendStringInfoString(buf, ", LOCK_ONLY");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, "EXCL_LOCK ");
+		appendStringInfoString(buf, ", EXCL_LOCK");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, "KEYSHR_LOCK ");
+		appendStringInfoString(buf, ", KEYSHR_LOCK");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, "KEYS_UPDATED ");
+		appendStringInfoString(buf, ", KEYS_UPDATED");
+
+	appendStringInfoString(buf, " ]");
+}
+
+static void
+plan_elem_desc(StringInfo buf, void *restrict plan, void *restrict data)
+{
+	xl_heap_freeze_plan *new_plan = (xl_heap_freeze_plan *) plan;
+	OffsetNumber **offsets = data;
+
+	appendStringInfo(buf, "{ xmax: %u, infomask: %u, infomask2: %u, ntuples: %u",
+					 new_plan->xmax, new_plan->t_infomask,
+					 new_plan->t_infomask2,
+					 new_plan->ntuples);
+
+	appendStringInfoString(buf, ", offsets:");
+	array_desc(buf, *offsets, sizeof(OffsetNumber), new_plan->ntuples,
+			   &offset_elem_desc, NULL);
+
+	*offsets += new_plan->ntuples;
+
+	appendStringInfo(buf, " }");
 }
 
+
 void
 heap_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -42,14 +76,15 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_insert *xlrec = (xl_heap_insert *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X", xlrec->offnum,
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+						 xlrec->offnum,
 						 xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_DELETE)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
 						 xlrec->offnum,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
@@ -58,12 +93,12 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
@@ -71,39 +106,41 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
-		int			i;
 
+		appendStringInfoString(buf, "flags: [");
 		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, "cascade ");
+			appendStringInfoString(buf, " CASCADE");
 		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, "restart_seqs ");
-		appendStringInfo(buf, "nrelids %u relids", xlrec->nrelids);
-		for (i = 0; i < xlrec->nrelids; i++)
-			appendStringInfo(buf, " %u", xlrec->relids[i]);
+			appendStringInfoString(buf, ", RESTART_SEQS");
+		appendStringInfoString(buf, " ]");
+
+		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
+		appendStringInfoString(buf, ", relids:");
+		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids, &relid_desc, NULL);
 	}
 	else if (info == XLOG_HEAP_CONFIRM)
 	{
 		xl_heap_confirm *xlrec = (xl_heap_confirm *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 	else if (info == XLOG_HEAP_LOCK)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off %u: xid %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -111,9 +148,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_inplace *xlrec = (xl_heap_inplace *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 }
+
 void
 heap2_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -125,43 +163,103 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_prune *xlrec = (xl_heap_prune *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nredirected %u ndead %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u",
 						 xlrec->snapshotConflictHorizon,
 						 xlrec->nredirected,
 						 xlrec->ndead);
+
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *end;
+			OffsetNumber *redirected;
+			OffsetNumber *nowdead;
+			OffsetNumber *nowunused;
+			int			nredirected;
+			int			nunused;
+			Size		datalen;
+
+			redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+			nredirected = xlrec->nredirected;
+			end = (OffsetNumber *) ((char *) redirected + datalen);
+			nowdead = redirected + (nredirected * 2);
+			nowunused = nowdead + xlrec->ndead;
+			nunused = (end - nowunused);
+			Assert(nunused >= 0);
+
+			appendStringInfo(buf, ", nunused: %u", nunused);
+
+			appendStringInfoString(buf, ", redirected:");
+			array_desc(buf, redirected, sizeof(OffsetNumber) * 2, nredirected * 2, &redirect_elem_desc, NULL);
+			appendStringInfoString(buf, ", dead:");
+			array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead, &offset_elem_desc, NULL);
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_VACUUM)
 	{
 		xl_heap_vacuum *xlrec = (xl_heap_vacuum *) rec;
 
-		appendStringInfo(buf, "nunused %u", xlrec->nunused);
+		appendStringInfo(buf, "nunused: %u", xlrec->nunused);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *nowunused;
+			Size		datalen;
+
+			nowunused = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), xlrec->nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_FREEZE_PAGE)
 	{
 		xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nplans %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u",
 						 xlrec->snapshotConflictHorizon, xlrec->nplans);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			xl_heap_freeze_plan *plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
+			OffsetNumber *offsets = (OffsetNumber *) &plans[xlrec->nplans];
+
+			appendStringInfoString(buf, ", plans");
+			array_desc(buf,
+					   plans,
+					   sizeof(xl_heap_freeze_plan),
+					   xlrec->nplans,
+					   &plan_elem_desc,
+					   &offsets);
+
+		}
 	}
 	else if (info == XLOG_HEAP2_VISIBLE)
 	{
 		xl_heap_visible *xlrec = (xl_heap_visible *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u flags 0x%02X",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, flags: 0x%02X",
 						 xlrec->snapshotConflictHorizon, xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_MULTI_INSERT)
 	{
 		xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
+		bool		isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
 
-		appendStringInfo(buf, "%d tuples flags 0x%02X", xlrec->ntuples,
+		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
+		appendStringInfoString(buf, ", offsets:");
+		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber), xlrec->ntuples, &offset_elem_desc, NULL);
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off %u: xmax %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -169,13 +267,13 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_new_cid *xlrec = (xl_heap_new_cid *) rec;
 
-		appendStringInfo(buf, "rel %u/%u/%u; tid %u/%u",
+		appendStringInfo(buf, "rel: %u/%u/%u, tid: %u/%u",
 						 xlrec->target_locator.spcOid,
 						 xlrec->target_locator.dbOid,
 						 xlrec->target_locator.relNumber,
 						 ItemPointerGetBlockNumber(&(xlrec->target_tid)),
 						 ItemPointerGetOffsetNumber(&(xlrec->target_tid)));
-		appendStringInfo(buf, "; cmin: %u, cmax: %u, combo: %u",
+		appendStringInfo(buf, ", cmin: %u, cmax: %u, combo: %u",
 						 xlrec->cmin, xlrec->cmax, xlrec->combocid);
 	}
 }
diff --git a/src/backend/access/rmgrdesc/meson.build b/src/backend/access/rmgrdesc/meson.build
index 166cee67b6..f76e87e2d7 100644
--- a/src/backend/access/rmgrdesc/meson.build
+++ b/src/backend/access/rmgrdesc/meson.build
@@ -16,6 +16,7 @@ rmgr_desc_sources = files(
   'nbtdesc.c',
   'relmapdesc.c',
   'replorigindesc.c',
+  'rmgrdesc_utils.c',
   'seqdesc.c',
   'smgrdesc.c',
   'spgdesc.c',
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
new file mode 100644
index 0000000000..fa45c796a0
--- /dev/null
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -0,0 +1,88 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.c
+ *		support functions for rmgrdesc
+ *
+ * Portions Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/rmgrdesc/rmgrdesc_utils.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/rmgrdesc_utils.h"
+
+/*
+ * The expected formatting of a desc function for an xlog record is as follows:
+ * member1_name: member1_value, member2_name: member2_value
+ * If the value is a list, please use
+ * member3_name: [ member3_list_value1, member3_list_value2 ]
+ *
+ * The first item appended to the string should not be prepended by any spaces
+ * or comma, however all subsequent appends to the string are responsible for
+ * prepended themselves with a comma followed by a space.
+ *
+ * Arrays should have a space between the opening square bracket and first
+ * element and between the last element and closing brace.
+ *
+ * Flags should be in all caps.
+ *
+ * For lists/arrays of items, the number of those items should be listed at the
+ * beginning with all the other numbers.
+ *
+ * whether or not to leave out a n[item] if the number is 0 (not consistent for
+ * XLOG_HEAP2_VACUUM and XLOG_HEAP2_PRUNE
+ *
+ * composite objects in a list should be surrounded with { }
+ *
+ * etc.
+ *
+ * TODO: make this description better/maybe put in a README
+ */
+
+
+void
+array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+		   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+		   void *restrict data)
+{
+	if (count == 0)
+	{
+		appendStringInfoString(buf, " []");
+		return;
+	}
+	appendStringInfo(buf, " [");
+	for (int i = 0; i < count; i++)
+	{
+		if (i > 0)
+			appendStringInfoString(buf, ",");
+		appendStringInfoString(buf, " ");
+
+		elem_desc(buf, (char *) array + elem_size * i, data);
+	}
+	appendStringInfoString(buf, " ]");
+}
+
+void
+redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	OffsetNumber *new_offset = (OffsetNumber *) offset;
+
+	appendStringInfo(buf, "%u->%u", new_offset[0], new_offset[1]);
+}
+
+void
+offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(OffsetNumber *) offset);
+}
+
+void
+relid_desc(StringInfo buf, void *restrict relid, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(Oid *) relid);
+}
diff --git a/src/bin/pg_waldump/Makefile b/src/bin/pg_waldump/Makefile
index d6459e17c7..61c9de470c 100644
--- a/src/bin/pg_waldump/Makefile
+++ b/src/bin/pg_waldump/Makefile
@@ -18,7 +18,7 @@ OBJS = \
 
 override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
 
-RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c)))
+RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c) $(top_srcdir)/src/backend/access/rmgrdesc/rmgrdesc_utils.c))
 RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
 
 
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 8cb0d8da19..e7a5179b9f 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -265,6 +265,7 @@ typedef struct xl_heap_vacuum
 #define SizeOfHeapVacuum (offsetof(xl_heap_vacuum, nunused) + sizeof(uint16))
 
 /* flags for infobits_set */
+// add a comment about this
 #define XLHL_XMAX_IS_MULTI		0x01
 #define XLHL_XMAX_LOCK_ONLY		0x02
 #define XLHL_XMAX_EXCL_LOCK		0x04
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
new file mode 100644
index 0000000000..7e4fcbdf25
--- /dev/null
+++ b/src/include/access/rmgrdesc_utils.h
@@ -0,0 +1,33 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.h
+ *	  helper utilities for rmgrdesc
+ *
+ * Copyright (c) 2023 PostgreSQL Global Development Group
+ *
+ * src/include/access/rmgrdesc_utils.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef RMGRDESC_UTILS_H_
+#define RMGRDESC_UTILS_H_
+
+#include "storage/off.h"
+#include "access/heapam_xlog.h"
+
+void
+			array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+					   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+					   void *restrict data);
+
+void
+			offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+void
+			redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+void
+			relid_desc(StringInfo buf, void *restrict relid, void *restrict data);
+
+
+#endif							/* RMGRDESC_UTILS_H */
-- 
2.38.1

From 8e2308b6b9047c42d3906943dec3fd11e975ef72 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Wed, 1 Mar 2023 10:53:41 -0500
Subject: [PATCH v1] Return block_ref details as an array

In pg_walinspect, the block_ref column was a string, making it difficult
to access individual members without regular expressions. Now it is an
int array of int arrays for each block with the relevant information.

Note that in the case of a compressed block image, the compression type
is not listed as it is a string.
---
 contrib/pg_walinspect/pg_walinspect--1.0.sql |   6 +-
 contrib/pg_walinspect/pg_walinspect.c        | 135 +++++++++++++++----
 2 files changed, 114 insertions(+), 27 deletions(-)

diff --git a/contrib/pg_walinspect/pg_walinspect--1.0.sql b/contrib/pg_walinspect/pg_walinspect--1.0.sql
index 08b3dd5556..eb8ff82dd8 100644
--- a/contrib/pg_walinspect/pg_walinspect--1.0.sql
+++ b/contrib/pg_walinspect/pg_walinspect--1.0.sql
@@ -17,7 +17,7 @@ CREATE FUNCTION pg_get_wal_record_info(IN in_lsn pg_lsn,
     OUT main_data_length int4,
     OUT fpi_length int4,
     OUT description text,
-    OUT block_ref text
+    OUT block_ref int4[][]
 )
 AS 'MODULE_PATHNAME', 'pg_get_wal_record_info'
 LANGUAGE C STRICT PARALLEL SAFE;
@@ -40,7 +40,7 @@ CREATE FUNCTION pg_get_wal_records_info(IN start_lsn pg_lsn,
     OUT main_data_length int4,
     OUT fpi_length int4,
     OUT description text,
-    OUT block_ref text
+    OUT block_ref int4[][]
 )
 RETURNS SETOF record
 AS 'MODULE_PATHNAME', 'pg_get_wal_records_info'
@@ -63,7 +63,7 @@ CREATE FUNCTION pg_get_wal_records_info_till_end_of_wal(IN start_lsn pg_lsn,
     OUT main_data_length int4,
     OUT fpi_length int4,
     OUT description text,
-    OUT block_ref text
+    OUT block_ref int4[][]
 )
 RETURNS SETOF record
 AS 'MODULE_PATHNAME', 'pg_get_wal_records_info_till_end_of_wal'
diff --git a/contrib/pg_walinspect/pg_walinspect.c b/contrib/pg_walinspect/pg_walinspect.c
index b7b0a805ee..446449bbe1 100644
--- a/contrib/pg_walinspect/pg_walinspect.c
+++ b/contrib/pg_walinspect/pg_walinspect.c
@@ -22,6 +22,7 @@
 #include "miscadmin.h"
 #include "utils/builtins.h"
 #include "utils/pg_lsn.h"
+#include "utils/array.h"
 
 /*
  * NOTE: For any code change or issue fix here, it is highly recommended to
@@ -57,6 +58,8 @@ static void FillXLogStatsRow(const char *name, uint64 n, uint64 total_count,
 static void GetWalStats(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
 						XLogRecPtr end_lsn, bool stats_per_record);
 static void GetWALFPIInfo(FunctionCallInfo fcinfo, XLogReaderState *record);
+static Datum
+walinspect_get_blkrefs(XLogReaderState *record, uint32 *fpi_data_size);
 
 /*
  * Check if the given LSN is in future. Also, return the LSN up to which the
@@ -174,6 +177,95 @@ ReadNextXLogRecord(XLogReaderState *xlogreader)
 	return record;
 }
 
+/* number of block ref items to display for every block (cols for our array) */
+#define WAL_BLOCK_INFO_TYPES 9
+
+static Datum
+walinspect_get_blkrefs(XLogReaderState *record, uint32 *fpi_data_size)
+{
+	DecodedBkpBlock *block;
+	ArrayType *aout;
+	Datum *cur_result;
+	Datum *result_datums;
+	bool *result_nulls;
+	int dims[2];
+	int lbs[2] = {0,0};
+	int nblocks = 0; /* nblocks is the number of rows of blocks */
+
+	int max_block_id  = XLogRecMaxBlockId(record);
+
+	/* determine how many blocks we have */
+	for (int block_id = 0; block_id <= max_block_id; block_id++)
+	{
+		if (XLogRecHasBlockRef(record, block_id))
+			nblocks++;
+	}
+
+	dims[0] = nblocks;
+	dims[1] = WAL_BLOCK_INFO_TYPES;
+
+	result_datums = palloc0(sizeof(Datum) * WAL_BLOCK_INFO_TYPES * nblocks);
+	result_nulls = palloc0(sizeof(bool) * WAL_BLOCK_INFO_TYPES * nblocks);
+
+	cur_result = result_datums;
+
+	for (int block_id = 0; block_id <= max_block_id; block_id++)
+	{
+		if (!XLogRecHasBlockRef(record, block_id))
+			continue;
+
+		block = XLogRecGetBlock(record, block_id);
+
+		*cur_result++ = Int32GetDatum(block_id);
+		*cur_result++ = Int32GetDatum(block->rlocator.spcOid);
+		*cur_result++ = Int32GetDatum(block->rlocator.dbOid);
+		*cur_result++ = Int32GetDatum(block->rlocator.relNumber);
+		*cur_result++ = Int32GetDatum(block->forknum);
+		*cur_result++ = Int32GetDatum(block->blkno);
+
+		if (!block->has_image)
+		{
+			cur_result += 3;
+			continue;
+		}
+
+		(*fpi_data_size) += block->bimg_len;
+
+		*cur_result++ = Int32GetDatum(block->hole_offset);
+		*cur_result++ = Int32GetDatum(block->hole_length);
+
+		if (!BKPIMAGE_COMPRESSED(block->bimg_info))
+		{
+			cur_result++;
+			continue;
+		}
+
+		*cur_result++ = Int32GetDatum(BLCKSZ - block->hole_length - block->bimg_len);
+	}
+
+	aout = construct_md_array(result_datums, result_nulls, 2, dims, lbs,
+			INT8OID, sizeof(int64), FLOAT8PASSBYVAL, TYPALIGN_DOUBLE);
+
+	PG_RETURN_POINTER(aout);
+}
+
+typedef enum wal_record_cols
+{
+	WAL_RECORD_START_LSN,
+	WAL_RECORD_END_LSN,
+	WAL_RECORD_PREV_LSN,
+	WAL_RECORD_XID,
+	WAL_RECORD_RMGR,
+	WAL_RECORD_TYPE,
+	WAL_RECORD_LENGTH,
+	WAL_RECORD_MAIN_DATA_LENGTH,
+	WAL_RECORD_FPI_LENGTH,
+	WAL_RECORD_DESC,
+	WAL_RECORD_BLOCK_REF
+} wal_record_cols;
+
+#define WAL_RECORD_NUM_COLS (WAL_RECORD_BLOCK_REF + 1)
+
 /*
  * Get a single WAL record info.
  */
@@ -183,40 +275,35 @@ GetWALRecordInfo(XLogReaderState *record, Datum *values,
 {
 	const char *id;
 	RmgrData	desc;
-	uint32		fpi_len = 0;
 	StringInfoData rec_desc;
-	StringInfoData rec_blk_ref;
-	uint32		main_data_len;
-	int			i = 0;
+	Datum blkref_array;
+	uint32		fpi_len = 0;
+
+	values[WAL_RECORD_START_LSN] = LSNGetDatum(record->ReadRecPtr);
+	values[WAL_RECORD_END_LSN] = LSNGetDatum(record->EndRecPtr);
+	values[WAL_RECORD_PREV_LSN] = LSNGetDatum(XLogRecGetPrev(record));
+	values[WAL_RECORD_XID] = TransactionIdGetDatum(XLogRecGetXid(record));
 
 	desc = GetRmgr(XLogRecGetRmid(record));
-	id = desc.rm_identify(XLogRecGetInfo(record));
+	values[WAL_RECORD_RMGR] = CStringGetTextDatum(desc.rm_name);
 
+	id = desc.rm_identify(XLogRecGetInfo(record));
 	if (id == NULL)
 		id = psprintf("UNKNOWN (%x)", XLogRecGetInfo(record) & ~XLR_INFO_MASK);
+	values[WAL_RECORD_TYPE] = CStringGetTextDatum(id);
 
-	initStringInfo(&rec_desc);
-	desc.rm_desc(&rec_desc, record);
-
-	/* Block references. */
-	initStringInfo(&rec_blk_ref);
-	XLogRecGetBlockRefInfo(record, false, true, &rec_blk_ref, &fpi_len);
+	values[WAL_RECORD_LENGTH] = UInt32GetDatum(XLogRecGetTotalLen(record));
+	values[WAL_RECORD_MAIN_DATA_LENGTH] = UInt32GetDatum(XLogRecGetDataLen(record));
 
-	main_data_len = XLogRecGetDataLen(record);
+	blkref_array = walinspect_get_blkrefs(record, &fpi_len);
 
-	values[i++] = LSNGetDatum(record->ReadRecPtr);
-	values[i++] = LSNGetDatum(record->EndRecPtr);
-	values[i++] = LSNGetDatum(XLogRecGetPrev(record));
-	values[i++] = TransactionIdGetDatum(XLogRecGetXid(record));
-	values[i++] = CStringGetTextDatum(desc.rm_name);
-	values[i++] = CStringGetTextDatum(id);
-	values[i++] = UInt32GetDatum(XLogRecGetTotalLen(record));
-	values[i++] = UInt32GetDatum(main_data_len);
-	values[i++] = UInt32GetDatum(fpi_len);
-	values[i++] = CStringGetTextDatum(rec_desc.data);
-	values[i++] = CStringGetTextDatum(rec_blk_ref.data);
+	values[WAL_RECORD_FPI_LENGTH] = UInt32GetDatum(fpi_len);
+	initStringInfo(&rec_desc);
+	desc.rm_desc(&rec_desc, record);
+	values[WAL_RECORD_DESC] = CStringGetTextDatum(rec_desc.data);
+	values[WAL_RECORD_BLOCK_REF] = blkref_array;
 
-	Assert(i == ncols);
+	Assert(ncols == WAL_RECORD_NUM_COLS);
 }
 
 
-- 
2.37.2

From 068f0caaf1188be2dcc979efc54979260ed53d5b Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Wed, 25 Jan 2023 08:38:38 -0500
Subject: [PATCH v2 1/2] Add rmgr_desc utilities

- Begin to standardize format of rmgr_desc output, adding a new
  rmgr_utils file with comments about expected format.
- Add helper which prints arrays in a standard format and use it in
  heapdesc to print out offset arrays, relid arrays, freeze plan arrays,
  and relid arrays
---
 src/backend/access/rmgrdesc/Makefile         |   1 +
 src/backend/access/rmgrdesc/heapdesc.c       | 153 +++++++++++++++----
 src/backend/access/rmgrdesc/meson.build      |   1 +
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  88 +++++++++++
 src/bin/pg_waldump/Makefile                  |   2 +-
 src/include/access/heapam_xlog.h             |   1 +
 src/include/access/rmgrdesc_utils.h          |  33 ++++
 7 files changed, 250 insertions(+), 29 deletions(-)
 create mode 100644 src/backend/access/rmgrdesc/rmgrdesc_utils.c
 create mode 100644 src/include/access/rmgrdesc_utils.h

diff --git a/src/backend/access/rmgrdesc/Makefile b/src/backend/access/rmgrdesc/Makefile
index f88d72fd86..cd95eec37f 100644
--- a/src/backend/access/rmgrdesc/Makefile
+++ b/src/backend/access/rmgrdesc/Makefile
@@ -23,6 +23,7 @@ OBJS = \
 	nbtdesc.o \
 	relmapdesc.o \
 	replorigindesc.o \
+	rmgrdesc_utils.o \
 	seqdesc.o \
 	smgrdesc.o \
 	spgdesc.o \
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e8215..38cff5ac26 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -15,22 +15,56 @@
 #include "postgres.h"
 
 #include "access/heapam_xlog.h"
+#include "access/rmgrdesc_utils.h"
+
 
 static void
 out_infobits(StringInfo buf, uint8 infobits)
 {
+	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
+		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
+		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
+		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
+		(infobits & XLHL_KEYS_UPDATED) == 0)
+		return;
+
+	appendStringInfoString(buf, ", infobits: [");
+
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, "IS_MULTI ");
+		appendStringInfoString(buf, " IS_MULTI");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, "LOCK_ONLY ");
+		appendStringInfoString(buf, ", LOCK_ONLY");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, "EXCL_LOCK ");
+		appendStringInfoString(buf, ", EXCL_LOCK");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, "KEYSHR_LOCK ");
+		appendStringInfoString(buf, ", KEYSHR_LOCK");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, "KEYS_UPDATED ");
+		appendStringInfoString(buf, ", KEYS_UPDATED");
+
+	appendStringInfoString(buf, " ]");
+}
+
+static void
+plan_elem_desc(StringInfo buf, void *restrict plan, void *restrict data)
+{
+	xl_heap_freeze_plan *new_plan = (xl_heap_freeze_plan *) plan;
+	OffsetNumber **offsets = data;
+
+	appendStringInfo(buf, "{ xmax: %u, infomask: %u, infomask2: %u, ntuples: %u",
+					 new_plan->xmax, new_plan->t_infomask,
+					 new_plan->t_infomask2,
+					 new_plan->ntuples);
+
+	appendStringInfoString(buf, ", offsets:");
+	array_desc(buf, *offsets, sizeof(OffsetNumber), new_plan->ntuples,
+			   &offset_elem_desc, NULL);
+
+	*offsets += new_plan->ntuples;
+
+	appendStringInfo(buf, " }");
 }
 
+
 void
 heap_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -42,14 +76,15 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_insert *xlrec = (xl_heap_insert *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X", xlrec->offnum,
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+						 xlrec->offnum,
 						 xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_DELETE)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
 						 xlrec->offnum,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
@@ -58,12 +93,12 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
@@ -71,39 +106,41 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
-		int			i;
 
+		appendStringInfoString(buf, "flags: [");
 		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, "cascade ");
+			appendStringInfoString(buf, " CASCADE");
 		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, "restart_seqs ");
-		appendStringInfo(buf, "nrelids %u relids", xlrec->nrelids);
-		for (i = 0; i < xlrec->nrelids; i++)
-			appendStringInfo(buf, " %u", xlrec->relids[i]);
+			appendStringInfoString(buf, ", RESTART_SEQS");
+		appendStringInfoString(buf, " ]");
+
+		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
+		appendStringInfoString(buf, ", relids:");
+		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids, &relid_desc, NULL);
 	}
 	else if (info == XLOG_HEAP_CONFIRM)
 	{
 		xl_heap_confirm *xlrec = (xl_heap_confirm *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 	else if (info == XLOG_HEAP_LOCK)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off %u: xid %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -111,9 +148,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_inplace *xlrec = (xl_heap_inplace *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 }
+
 void
 heap2_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -125,43 +163,102 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_prune *xlrec = (xl_heap_prune *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nredirected %u ndead %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u",
 						 xlrec->snapshotConflictHorizon,
 						 xlrec->nredirected,
 						 xlrec->ndead);
+
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *end;
+			OffsetNumber *redirected;
+			OffsetNumber *nowdead;
+			OffsetNumber *nowunused;
+			int			nredirected;
+			int			nunused;
+			Size		datalen;
+
+			redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+			nredirected = xlrec->nredirected;
+			end = (OffsetNumber *) ((char *) redirected + datalen);
+			nowdead = redirected + (nredirected * 2);
+			nowunused = nowdead + xlrec->ndead;
+			nunused = (end - nowunused);
+			Assert(nunused >= 0);
+
+			appendStringInfo(buf, ", nunused: %u", nunused);
+
+			appendStringInfoString(buf, ", redirected:");
+			array_desc(buf, redirected, sizeof(OffsetNumber) * 2, nredirected * 2, &redirect_elem_desc, NULL);
+			appendStringInfoString(buf, ", dead:");
+			array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead, &offset_elem_desc, NULL);
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_VACUUM)
 	{
 		xl_heap_vacuum *xlrec = (xl_heap_vacuum *) rec;
 
-		appendStringInfo(buf, "nunused %u", xlrec->nunused);
+		appendStringInfo(buf, "nunused: %u", xlrec->nunused);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *nowunused;
+
+			nowunused = (OffsetNumber *) XLogRecGetBlockData(record, 0, NULL);
+
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), xlrec->nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_FREEZE_PAGE)
 	{
 		xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nplans %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u",
 						 xlrec->snapshotConflictHorizon, xlrec->nplans);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			xl_heap_freeze_plan *plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
+			OffsetNumber *offsets = (OffsetNumber *) &plans[xlrec->nplans];
+
+			appendStringInfoString(buf, ", plans:");
+			array_desc(buf,
+					   plans,
+					   sizeof(xl_heap_freeze_plan),
+					   xlrec->nplans,
+					   &plan_elem_desc,
+					   &offsets);
+
+		}
 	}
 	else if (info == XLOG_HEAP2_VISIBLE)
 	{
 		xl_heap_visible *xlrec = (xl_heap_visible *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u flags 0x%02X",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, flags: 0x%02X",
 						 xlrec->snapshotConflictHorizon, xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_MULTI_INSERT)
 	{
 		xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
+		bool		isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
 
-		appendStringInfo(buf, "%d tuples flags 0x%02X", xlrec->ntuples,
+		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
+		appendStringInfoString(buf, ", offsets:");
+		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber), xlrec->ntuples, &offset_elem_desc, NULL);
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off %u: xmax %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -169,13 +266,13 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_new_cid *xlrec = (xl_heap_new_cid *) rec;
 
-		appendStringInfo(buf, "rel %u/%u/%u; tid %u/%u",
+		appendStringInfo(buf, "rel: %u/%u/%u, tid: %u/%u",
 						 xlrec->target_locator.spcOid,
 						 xlrec->target_locator.dbOid,
 						 xlrec->target_locator.relNumber,
 						 ItemPointerGetBlockNumber(&(xlrec->target_tid)),
 						 ItemPointerGetOffsetNumber(&(xlrec->target_tid)));
-		appendStringInfo(buf, "; cmin: %u, cmax: %u, combo: %u",
+		appendStringInfo(buf, ", cmin: %u, cmax: %u, combo: %u",
 						 xlrec->cmin, xlrec->cmax, xlrec->combocid);
 	}
 }
diff --git a/src/backend/access/rmgrdesc/meson.build b/src/backend/access/rmgrdesc/meson.build
index 166cee67b6..f76e87e2d7 100644
--- a/src/backend/access/rmgrdesc/meson.build
+++ b/src/backend/access/rmgrdesc/meson.build
@@ -16,6 +16,7 @@ rmgr_desc_sources = files(
   'nbtdesc.c',
   'relmapdesc.c',
   'replorigindesc.c',
+  'rmgrdesc_utils.c',
   'seqdesc.c',
   'smgrdesc.c',
   'spgdesc.c',
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
new file mode 100644
index 0000000000..fa45c796a0
--- /dev/null
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -0,0 +1,88 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.c
+ *		support functions for rmgrdesc
+ *
+ * Portions Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/rmgrdesc/rmgrdesc_utils.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/rmgrdesc_utils.h"
+
+/*
+ * The expected formatting of a desc function for an xlog record is as follows:
+ * member1_name: member1_value, member2_name: member2_value
+ * If the value is a list, please use
+ * member3_name: [ member3_list_value1, member3_list_value2 ]
+ *
+ * The first item appended to the string should not be prepended by any spaces
+ * or comma, however all subsequent appends to the string are responsible for
+ * prepended themselves with a comma followed by a space.
+ *
+ * Arrays should have a space between the opening square bracket and first
+ * element and between the last element and closing brace.
+ *
+ * Flags should be in all caps.
+ *
+ * For lists/arrays of items, the number of those items should be listed at the
+ * beginning with all the other numbers.
+ *
+ * whether or not to leave out a n[item] if the number is 0 (not consistent for
+ * XLOG_HEAP2_VACUUM and XLOG_HEAP2_PRUNE
+ *
+ * composite objects in a list should be surrounded with { }
+ *
+ * etc.
+ *
+ * TODO: make this description better/maybe put in a README
+ */
+
+
+void
+array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+		   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+		   void *restrict data)
+{
+	if (count == 0)
+	{
+		appendStringInfoString(buf, " []");
+		return;
+	}
+	appendStringInfo(buf, " [");
+	for (int i = 0; i < count; i++)
+	{
+		if (i > 0)
+			appendStringInfoString(buf, ",");
+		appendStringInfoString(buf, " ");
+
+		elem_desc(buf, (char *) array + elem_size * i, data);
+	}
+	appendStringInfoString(buf, " ]");
+}
+
+void
+redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	OffsetNumber *new_offset = (OffsetNumber *) offset;
+
+	appendStringInfo(buf, "%u->%u", new_offset[0], new_offset[1]);
+}
+
+void
+offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(OffsetNumber *) offset);
+}
+
+void
+relid_desc(StringInfo buf, void *restrict relid, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(Oid *) relid);
+}
diff --git a/src/bin/pg_waldump/Makefile b/src/bin/pg_waldump/Makefile
index d6459e17c7..61c9de470c 100644
--- a/src/bin/pg_waldump/Makefile
+++ b/src/bin/pg_waldump/Makefile
@@ -18,7 +18,7 @@ OBJS = \
 
 override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
 
-RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c)))
+RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c) $(top_srcdir)/src/backend/access/rmgrdesc/rmgrdesc_utils.c))
 RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
 
 
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index a2c67d1cd3..63075c51bd 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -265,6 +265,7 @@ typedef struct xl_heap_vacuum
 #define SizeOfHeapVacuum (offsetof(xl_heap_vacuum, nunused) + sizeof(uint16))
 
 /* flags for infobits_set */
+// add a comment about this
 #define XLHL_XMAX_IS_MULTI		0x01
 #define XLHL_XMAX_LOCK_ONLY		0x02
 #define XLHL_XMAX_EXCL_LOCK		0x04
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
new file mode 100644
index 0000000000..7e4fcbdf25
--- /dev/null
+++ b/src/include/access/rmgrdesc_utils.h
@@ -0,0 +1,33 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.h
+ *	  helper utilities for rmgrdesc
+ *
+ * Copyright (c) 2023 PostgreSQL Global Development Group
+ *
+ * src/include/access/rmgrdesc_utils.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef RMGRDESC_UTILS_H_
+#define RMGRDESC_UTILS_H_
+
+#include "storage/off.h"
+#include "access/heapam_xlog.h"
+
+void
+			array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+					   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+					   void *restrict data);
+
+void
+			offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+void
+			redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+void
+			relid_desc(StringInfo buf, void *restrict relid, void *restrict data);
+
+
+#endif							/* RMGRDESC_UTILS_H */
-- 
2.37.2

From 9a8a9d01bcd2e18e5f6240c7aedd0f982734c860 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Mon, 13 Mar 2023 18:15:17 -0400
Subject: [PATCH v2 2/2] Add detail to some btree xlog records

---
 src/backend/access/rmgrdesc/nbtdesc.c        | 81 +++++++++++++++++---
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  6 ++
 src/include/access/rmgrdesc_utils.h          |  3 +
 3 files changed, 78 insertions(+), 12 deletions(-)

diff --git a/src/backend/access/rmgrdesc/nbtdesc.c b/src/backend/access/rmgrdesc/nbtdesc.c
index c5dc543a0f..3f2f19aad7 100644
--- a/src/backend/access/rmgrdesc/nbtdesc.c
+++ b/src/backend/access/rmgrdesc/nbtdesc.c
@@ -15,6 +15,53 @@
 #include "postgres.h"
 
 #include "access/nbtxlog.h"
+#include "access/rmgrdesc_utils.h"
+
+static void
+btree_update_elem_desc(StringInfo buf, void *restrict update, void *restrict data)
+{
+	xl_btree_update *new_update = (xl_btree_update *) update;
+	OffsetNumber *updated_offset = *((OffsetNumber **) data);
+
+	appendStringInfo(buf, "{ updated offset: %u, ndeleted tids: %u", *updated_offset, new_update->ndeletedtids);
+
+	appendStringInfoString(buf, ", deleted tids:");
+
+	array_desc(buf, (char *) new_update + SizeOfBtreeUpdate,
+			sizeof(uint16), new_update->ndeletedtids, &uint16_elem_desc, NULL);
+
+	updated_offset++;
+
+	appendStringInfo(buf, " }");
+}
+
+static void
+btree_del_desc(StringInfo buf, char *block_data, uint16 ndeleted, uint16 nupdated)
+{
+	OffsetNumber *updatedoffsets;
+	xl_btree_update *updates;
+	OffsetNumber *data = (OffsetNumber *) block_data;
+
+	appendStringInfoString(buf, ", deleted:");
+	array_desc(buf, data, sizeof(OffsetNumber), ndeleted, &offset_elem_desc, NULL);
+
+	appendStringInfoString(buf, ", updated:");
+	array_desc(buf, data, sizeof(OffsetNumber), nupdated, &offset_elem_desc, NULL);
+
+	if (nupdated <= 0)
+		return;
+
+	updatedoffsets = (OffsetNumber *)
+		((char *) data + ndeleted * sizeof(OffsetNumber));
+	updates = (xl_btree_update *) ((char *) updatedoffsets +
+								nupdated *
+								sizeof(OffsetNumber));
+
+	appendStringInfoString(buf, ", updates:");
+	array_desc(buf, updates, sizeof(xl_btree_update),
+			nupdated, &btree_update_elem_desc,
+			&updatedoffsets);
+}
 
 void
 btree_desc(StringInfo buf, XLogReaderState *record)
@@ -31,7 +78,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_insert *xlrec = (xl_btree_insert *) rec;
 
-				appendStringInfo(buf, "off %u", xlrec->offnum);
+				appendStringInfo(buf, "off: %u", xlrec->offnum);
 				break;
 			}
 		case XLOG_BTREE_SPLIT_L:
@@ -39,7 +86,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_split *xlrec = (xl_btree_split *) rec;
 
-				appendStringInfo(buf, "level %u, firstrightoff %d, newitemoff %d, postingoff %d",
+				appendStringInfo(buf, "level: %u, firstrightoff: %d, newitemoff: %d, postingoff: %d",
 								 xlrec->level, xlrec->firstrightoff,
 								 xlrec->newitemoff, xlrec->postingoff);
 				break;
@@ -48,31 +95,41 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_dedup *xlrec = (xl_btree_dedup *) rec;
 
-				appendStringInfo(buf, "nintervals %u", xlrec->nintervals);
+				appendStringInfo(buf, "nintervals: %u", xlrec->nintervals);
 				break;
 			}
 		case XLOG_BTREE_VACUUM:
 			{
 				xl_btree_vacuum *xlrec = (xl_btree_vacuum *) rec;
 
-				appendStringInfo(buf, "ndeleted %u; nupdated %u",
-								 xlrec->ndeleted, xlrec->nupdated);
+				appendStringInfo(buf, "ndeleted: %u, nupdated: %u",
+						xlrec->ndeleted, xlrec->nupdated);
+
+				if (!XLogRecHasBlockImage(record, 0))
+					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+							xlrec->ndeleted, xlrec->nupdated);
+
 				break;
 			}
 		case XLOG_BTREE_DELETE:
 			{
 				xl_btree_delete *xlrec = (xl_btree_delete *) rec;
 
-				appendStringInfo(buf, "snapshotConflictHorizon %u; ndeleted %u; nupdated %u",
+				appendStringInfo(buf, "snapshotConflictHorizon: %u, ndeleted: %u, nupdated: %u",
 								 xlrec->snapshotConflictHorizon,
 								 xlrec->ndeleted, xlrec->nupdated);
+
+				if (!XLogRecHasBlockImage(record, 0))
+					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+							xlrec->ndeleted, xlrec->nupdated);
+
 				break;
 			}
 		case XLOG_BTREE_MARK_PAGE_HALFDEAD:
 			{
 				xl_btree_mark_page_halfdead *xlrec = (xl_btree_mark_page_halfdead *) rec;
 
-				appendStringInfo(buf, "topparent %u; leaf %u; left %u; right %u",
+				appendStringInfo(buf, "topparent: %u; leaf: %u; left: %u; right: %u",
 								 xlrec->topparent, xlrec->leafblk, xlrec->leftblk, xlrec->rightblk);
 				break;
 			}
@@ -81,11 +138,11 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_unlink_page *xlrec = (xl_btree_unlink_page *) rec;
 
-				appendStringInfo(buf, "left %u; right %u; level %u; safexid %u:%u; ",
+				appendStringInfo(buf, "left: %u; right: %u; level: %u; safexid: %u:%u; ",
 								 xlrec->leftsib, xlrec->rightsib, xlrec->level,
 								 EpochFromFullTransactionId(xlrec->safexid),
 								 XidFromFullTransactionId(xlrec->safexid));
-				appendStringInfo(buf, "leafleft %u; leafright %u; leaftopparent %u",
+				appendStringInfo(buf, "leafleft: %u; leafright: %u; leaftopparent: %u",
 								 xlrec->leafleftsib, xlrec->leafrightsib,
 								 xlrec->leaftopparent);
 				break;
@@ -94,14 +151,14 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_newroot *xlrec = (xl_btree_newroot *) rec;
 
-				appendStringInfo(buf, "lev %u", xlrec->level);
+				appendStringInfo(buf, "lev: %u", xlrec->level);
 				break;
 			}
 		case XLOG_BTREE_REUSE_PAGE:
 			{
 				xl_btree_reuse_page *xlrec = (xl_btree_reuse_page *) rec;
 
-				appendStringInfo(buf, "rel %u/%u/%u; snapshotConflictHorizon %u:%u",
+				appendStringInfo(buf, "rel: %u/%u/%u, snapshotConflictHorizon: %u:%u",
 								 xlrec->locator.spcOid, xlrec->locator.dbOid,
 								 xlrec->locator.relNumber,
 								 EpochFromFullTransactionId(xlrec->snapshotConflictHorizon),
@@ -114,7 +171,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 
 				xlrec = (xl_btree_metadata *) XLogRecGetBlockData(record, 0,
 																  NULL);
-				appendStringInfo(buf, "last_cleanup_num_delpages %u",
+				appendStringInfo(buf, "last_cleanup_num_delpages: %u",
 								 xlrec->last_cleanup_num_delpages);
 				break;
 			}
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index fa45c796a0..26da7e344f 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -86,3 +86,9 @@ relid_desc(StringInfo buf, void *restrict relid, void *restrict data)
 {
 	appendStringInfo(buf, "%u", *(Oid *) relid);
 }
+
+void
+uint16_elem_desc(StringInfo buf, void *restrict value, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(uint16 *) value);
+}
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 7e4fcbdf25..ddf50335b1 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -29,5 +29,8 @@ void
 void
 			relid_desc(StringInfo buf, void *restrict relid, void *restrict data);
 
+void
+			uint16_elem_desc(StringInfo buf, void *restrict value, void *restrict data);
+
 
 #endif							/* RMGRDESC_UTILS_H */
-- 
2.37.2

From b584717e9de72c1ac084698453667cb301551e36 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Tue, 21 Mar 2023 14:40:43 -0700
Subject: [PATCH v1] Record which PRUNE records are from VACUUM.

---
 src/include/access/heapam.h            |  2 +-
 src/include/access/heapam_xlog.h       |  8 +++++++-
 src/backend/access/heap/pruneheap.c    | 25 +++++++++++++++----------
 src/backend/access/rmgrdesc/heapdesc.c |  3 +++
 4 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index faf502651..2eedd7efd 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -289,7 +289,7 @@ extern int	heap_page_prune(Relation relation, Buffer buffer,
 							TransactionId old_snap_xmin,
 							TimestampTz old_snap_ts,
 							int *nnewlpdead,
-							OffsetNumber *off_loc);
+							OffsetNumber *off_loc_vacuum);
 extern void heap_page_prune_execute(Buffer buffer,
 									OffsetNumber *redirected, int nredirected,
 									OffsetNumber *nowdead, int ndead,
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index a2c67d1cd..3372d1938 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -48,7 +48,7 @@
  * We ran out of opcodes, so heapam.c now has a second RmgrId.  These opcodes
  * are associated with RM_HEAP2_ID, but are not logically different from
  * the ones above associated with RM_HEAP_ID.  XLOG_HEAP_OPMASK applies to
- * these, too.
+ * these, too.  The BYVACUUM bit is used in place of RM_HEAP_ID's init bit.
  */
 #define XLOG_HEAP2_REWRITE		0x00
 #define XLOG_HEAP2_PRUNE		0x10
@@ -59,6 +59,12 @@
 #define XLOG_HEAP2_LOCK_UPDATED 0x60
 #define XLOG_HEAP2_NEW_CID		0x70
 
+/*
+ * RM_HEAP2_ID operations that take place during VACUUM set the BYVACUUM bit
+ * as instrumentation.  Only set in XLOG_HEAP2_PRUNE records, for now.
+ */
+#define XLOG_HEAP2_BYVACUUM		0x80
+
 /*
  * xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
  */
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 4e65cbcad..5f4ef384e 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -257,8 +257,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  * Sets *nnewlpdead for caller, indicating the number of items that were
  * newly set LP_DEAD during prune operation.
  *
- * off_loc is the offset location required by the caller to use in error
- * callback.
+ * off_loc_vacuum is the offset location required by VACUUM caller to use in
+ * error callback.  Opportunistic pruning caller should pass NULL.
  *
  * Returns the number of tuples deleted from the page during this call.
  */
@@ -268,7 +268,7 @@ heap_page_prune(Relation relation, Buffer buffer,
 				TransactionId old_snap_xmin,
 				TimestampTz old_snap_ts,
 				int *nnewlpdead,
-				OffsetNumber *off_loc)
+				OffsetNumber *off_loc_vacuum)
 {
 	int			ndeleted = 0;
 	Page		page = BufferGetPage(buffer);
@@ -345,8 +345,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 		 * Set the offset number so that we can display it along with any
 		 * error that occurred while processing this tuple.
 		 */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		prstate.htsv[offnum] = heap_prune_satisfies_vacuum(&prstate, &tup,
 														   buffer);
@@ -364,8 +364,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 			continue;
 
 		/* see preceding loop */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		/* Nothing to do if slot is empty or already dead */
 		itemid = PageGetItemId(page, offnum);
@@ -377,8 +377,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 	}
 
 	/* Clear the offset information once we have processed the given page. */
-	if (off_loc)
-		*off_loc = InvalidOffsetNumber;
+	if (off_loc_vacuum)
+		*off_loc_vacuum = InvalidOffsetNumber;
 
 	/* Any error while applying the changes is critical */
 	START_CRIT_SECTION();
@@ -416,6 +416,7 @@ heap_page_prune(Relation relation, Buffer buffer,
 		if (RelationNeedsWAL(relation))
 		{
 			xl_heap_prune xlrec;
+			uint8		info = XLOG_HEAP2_PRUNE;
 			XLogRecPtr	recptr;
 
 			xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
@@ -445,7 +446,11 @@ heap_page_prune(Relation relation, Buffer buffer,
 				XLogRegisterBufData(0, (char *) prstate.nowunused,
 									prstate.nunused * sizeof(OffsetNumber));
 
-			recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+			/* Set bit indicating pruning by VACUUM where appropriate */
+			if (off_loc_vacuum)
+				info |= XLOG_HEAP2_BYVACUUM;
+
+			recptr = XLogInsert(RM_HEAP2_ID, info);
 
 			PageSetLSN(BufferGetPage(buffer), recptr);
 		}
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e821..9231b7411 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -235,6 +235,9 @@ heap2_identify(uint8 info)
 		case XLOG_HEAP2_PRUNE:
 			id = "PRUNE";
 			break;
+		case XLOG_HEAP2_PRUNE | XLOG_HEAP2_BYVACUUM:
+			id = "PRUNE+BYVACUUM";
+			break;
 		case XLOG_HEAP2_VACUUM:
 			id = "VACUUM";
 			break;
-- 
2.39.2

From b584717e9de72c1ac084698453667cb301551e36 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Tue, 21 Mar 2023 14:40:43 -0700
Subject: [PATCH v1] Record which PRUNE records are from VACUUM.

---
 src/include/access/heapam.h            |  2 +-
 src/include/access/heapam_xlog.h       |  8 +++++++-
 src/backend/access/heap/pruneheap.c    | 25 +++++++++++++++----------
 src/backend/access/rmgrdesc/heapdesc.c |  3 +++
 4 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index faf502651..2eedd7efd 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -289,7 +289,7 @@ extern int	heap_page_prune(Relation relation, Buffer buffer,
 							TransactionId old_snap_xmin,
 							TimestampTz old_snap_ts,
 							int *nnewlpdead,
-							OffsetNumber *off_loc);
+							OffsetNumber *off_loc_vacuum);
 extern void heap_page_prune_execute(Buffer buffer,
 									OffsetNumber *redirected, int nredirected,
 									OffsetNumber *nowdead, int ndead,
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index a2c67d1cd..3372d1938 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -48,7 +48,7 @@
  * We ran out of opcodes, so heapam.c now has a second RmgrId.  These opcodes
  * are associated with RM_HEAP2_ID, but are not logically different from
  * the ones above associated with RM_HEAP_ID.  XLOG_HEAP_OPMASK applies to
- * these, too.
+ * these, too.  The BYVACUUM bit is used in place of RM_HEAP_ID's init bit.
  */
 #define XLOG_HEAP2_REWRITE		0x00
 #define XLOG_HEAP2_PRUNE		0x10
@@ -59,6 +59,12 @@
 #define XLOG_HEAP2_LOCK_UPDATED 0x60
 #define XLOG_HEAP2_NEW_CID		0x70
 
+/*
+ * RM_HEAP2_ID operations that take place during VACUUM set the BYVACUUM bit
+ * as instrumentation.  Only set in XLOG_HEAP2_PRUNE records, for now.
+ */
+#define XLOG_HEAP2_BYVACUUM		0x80
+
 /*
  * xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
  */
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 4e65cbcad..5f4ef384e 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -257,8 +257,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  * Sets *nnewlpdead for caller, indicating the number of items that were
  * newly set LP_DEAD during prune operation.
  *
- * off_loc is the offset location required by the caller to use in error
- * callback.
+ * off_loc_vacuum is the offset location required by VACUUM caller to use in
+ * error callback.  Opportunistic pruning caller should pass NULL.
  *
  * Returns the number of tuples deleted from the page during this call.
  */
@@ -268,7 +268,7 @@ heap_page_prune(Relation relation, Buffer buffer,
 				TransactionId old_snap_xmin,
 				TimestampTz old_snap_ts,
 				int *nnewlpdead,
-				OffsetNumber *off_loc)
+				OffsetNumber *off_loc_vacuum)
 {
 	int			ndeleted = 0;
 	Page		page = BufferGetPage(buffer);
@@ -345,8 +345,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 		 * Set the offset number so that we can display it along with any
 		 * error that occurred while processing this tuple.
 		 */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		prstate.htsv[offnum] = heap_prune_satisfies_vacuum(&prstate, &tup,
 														   buffer);
@@ -364,8 +364,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 			continue;
 
 		/* see preceding loop */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		/* Nothing to do if slot is empty or already dead */
 		itemid = PageGetItemId(page, offnum);
@@ -377,8 +377,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 	}
 
 	/* Clear the offset information once we have processed the given page. */
-	if (off_loc)
-		*off_loc = InvalidOffsetNumber;
+	if (off_loc_vacuum)
+		*off_loc_vacuum = InvalidOffsetNumber;
 
 	/* Any error while applying the changes is critical */
 	START_CRIT_SECTION();
@@ -416,6 +416,7 @@ heap_page_prune(Relation relation, Buffer buffer,
 		if (RelationNeedsWAL(relation))
 		{
 			xl_heap_prune xlrec;
+			uint8		info = XLOG_HEAP2_PRUNE;
 			XLogRecPtr	recptr;
 
 			xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
@@ -445,7 +446,11 @@ heap_page_prune(Relation relation, Buffer buffer,
 				XLogRegisterBufData(0, (char *) prstate.nowunused,
 									prstate.nunused * sizeof(OffsetNumber));
 
-			recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+			/* Set bit indicating pruning by VACUUM where appropriate */
+			if (off_loc_vacuum)
+				info |= XLOG_HEAP2_BYVACUUM;
+
+			recptr = XLogInsert(RM_HEAP2_ID, info);
 
 			PageSetLSN(BufferGetPage(buffer), recptr);
 		}
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e821..9231b7411 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -235,6 +235,9 @@ heap2_identify(uint8 info)
 		case XLOG_HEAP2_PRUNE:
 			id = "PRUNE";
 			break;
+		case XLOG_HEAP2_PRUNE | XLOG_HEAP2_BYVACUUM:
+			id = "PRUNE+BYVACUUM";
+			break;
 		case XLOG_HEAP2_VACUUM:
 			id = "VACUUM";
 			break;
-- 
2.39.2

From 5b33b8fa323db65f3cf3b0dcc343071a7975b649 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Wed, 25 Jan 2023 08:38:38 -0500
Subject: [PATCH v3 1/2] Add rmgr_desc utilities

- Begin to standardize format of rmgr_desc output, adding a new
  rmgr_utils file with comments about expected format.
- Add helper which prints arrays in a standard format and use it in
  heapdesc to print out offset arrays, relid arrays, freeze plan arrays,
  and redirect arrays.

Suggested by Andres Freund

Discussion: https://postgr.es/m/flat/20230109215842.fktuhesvayno6o4g%40awork3.anarazel.de
---
 doc/src/sgml/pgwalinspect.sgml               |  14 +-
 src/backend/access/rmgrdesc/Makefile         |   1 +
 src/backend/access/rmgrdesc/heapdesc.c       | 152 +++++++++++++++----
 src/backend/access/rmgrdesc/meson.build      |   1 +
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  82 ++++++++++
 src/bin/pg_waldump/Makefile                  |   2 +-
 src/include/access/rmgrdesc_utils.h          |  29 ++++
 7 files changed, 245 insertions(+), 36 deletions(-)
 create mode 100644 src/backend/access/rmgrdesc/rmgrdesc_utils.c
 create mode 100644 src/include/access/rmgrdesc_utils.h

diff --git a/doc/src/sgml/pgwalinspect.sgml b/doc/src/sgml/pgwalinspect.sgml
index d9ed8f0a9a..7fb089e83a 100644
--- a/doc/src/sgml/pgwalinspect.sgml
+++ b/doc/src/sgml/pgwalinspect.sgml
@@ -110,18 +110,18 @@ block_ref        | blkref #0: rel 1663/5/60221 fork main blk 2
       Returns one row per WAL record.  For example:
 <screen>
 postgres=# SELECT * FROM pg_get_wal_records_info('0/1E913618', '0/1E913740') LIMIT 1;
--[ RECORD 1 ]----+--------------------------------------------------------------
+-[ RECORD 1 ]----+------------------------------------------------------------------------------------------------------------------------
 start_lsn        | 0/1E913618
 end_lsn          | 0/1E913650
 prev_lsn         | 0/1E9135A0
 xid              | 0
-resource_manager | Standby
-record_type      | RUNNING_XACTS
-record_length    | 50
-main_data_length | 24
+resource_manager | Heap2
+record_type      | PRUNE
+record_length    | 61
+main_data_length | 9
 fpi_length       | 0
-description      | nextXid 33775 latestCompletedXid 33774 oldestRunningXid 33775
-block_ref        |
+description      | snapshotConflictHorizon: 754, nredirected: 1, ndead: 1, nunused: 0, redirected: [ 1->5, 6->5 ], dead: [ 6 ], unused: []
+block_ref        | blkref #0: rel 1663/5/1259 fork main blk 1
 </screen>
      </para>
      <para>
diff --git a/src/backend/access/rmgrdesc/Makefile b/src/backend/access/rmgrdesc/Makefile
index f88d72fd86..cd95eec37f 100644
--- a/src/backend/access/rmgrdesc/Makefile
+++ b/src/backend/access/rmgrdesc/Makefile
@@ -23,6 +23,7 @@ OBJS = \
 	nbtdesc.o \
 	relmapdesc.o \
 	replorigindesc.o \
+	rmgrdesc_utils.o \
 	seqdesc.o \
 	smgrdesc.o \
 	spgdesc.o \
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e8215..1041db239f 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -15,20 +15,53 @@
 #include "postgres.h"
 
 #include "access/heapam_xlog.h"
+#include "access/rmgrdesc_utils.h"
+
 
 static void
 out_infobits(StringInfo buf, uint8 infobits)
 {
+	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
+		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
+		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
+		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
+		(infobits & XLHL_KEYS_UPDATED) == 0)
+		return;
+
+	appendStringInfoString(buf, ", infobits: [");
+
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, "IS_MULTI ");
+		appendStringInfoString(buf, " IS_MULTI");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, "LOCK_ONLY ");
+		appendStringInfoString(buf, ", LOCK_ONLY");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, "EXCL_LOCK ");
+		appendStringInfoString(buf, ", EXCL_LOCK");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, "KEYSHR_LOCK ");
+		appendStringInfoString(buf, ", KEYSHR_LOCK");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, "KEYS_UPDATED ");
+		appendStringInfoString(buf, ", KEYS_UPDATED");
+
+	appendStringInfoString(buf, " ]");
+}
+
+static void
+plan_elem_desc(StringInfo buf, void *restrict plan, void *restrict data)
+{
+	xl_heap_freeze_plan *new_plan = (xl_heap_freeze_plan *) plan;
+	OffsetNumber **offsets = data;
+
+	appendStringInfo(buf, "{ xmax: %u, infomask: %u, infomask2: %u, ntuples: %u",
+					 new_plan->xmax, new_plan->t_infomask,
+					 new_plan->t_infomask2,
+					 new_plan->ntuples);
+
+	appendStringInfoString(buf, ", offsets:");
+	array_desc(buf, *offsets, sizeof(OffsetNumber), new_plan->ntuples,
+			   &offset_elem_desc, NULL);
+
+	*offsets += new_plan->ntuples;
+
+	appendStringInfo(buf, " }");
 }
 
 void
@@ -42,14 +75,15 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_insert *xlrec = (xl_heap_insert *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X", xlrec->offnum,
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+						 xlrec->offnum,
 						 xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_DELETE)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
 						 xlrec->offnum,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
@@ -58,12 +92,12 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
@@ -71,39 +105,41 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
-		int			i;
 
+		appendStringInfoString(buf, "flags: [");
 		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, "cascade ");
+			appendStringInfoString(buf, " CASCADE");
 		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, "restart_seqs ");
-		appendStringInfo(buf, "nrelids %u relids", xlrec->nrelids);
-		for (i = 0; i < xlrec->nrelids; i++)
-			appendStringInfo(buf, " %u", xlrec->relids[i]);
+			appendStringInfoString(buf, ", RESTART_SEQS");
+		appendStringInfoString(buf, " ]");
+
+		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
+		appendStringInfoString(buf, ", relids:");
+		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids, &relid_desc, NULL);
 	}
 	else if (info == XLOG_HEAP_CONFIRM)
 	{
 		xl_heap_confirm *xlrec = (xl_heap_confirm *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 	else if (info == XLOG_HEAP_LOCK)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off %u: xid %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -111,9 +147,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_inplace *xlrec = (xl_heap_inplace *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 }
+
 void
 heap2_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -125,43 +162,102 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_prune *xlrec = (xl_heap_prune *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nredirected %u ndead %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u",
 						 xlrec->snapshotConflictHorizon,
 						 xlrec->nredirected,
 						 xlrec->ndead);
+
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *end;
+			OffsetNumber *redirected;
+			OffsetNumber *nowdead;
+			OffsetNumber *nowunused;
+			int			nredirected;
+			int			nunused;
+			Size		datalen;
+
+			redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+			nredirected = xlrec->nredirected;
+			end = (OffsetNumber *) ((char *) redirected + datalen);
+			nowdead = redirected + (nredirected * 2);
+			nowunused = nowdead + xlrec->ndead;
+			nunused = (end - nowunused);
+			Assert(nunused >= 0);
+
+			appendStringInfo(buf, ", nunused: %u", nunused);
+
+			appendStringInfoString(buf, ", redirected:");
+			array_desc(buf, redirected, sizeof(OffsetNumber) * 2, nredirected * 2, &redirect_elem_desc, NULL);
+			appendStringInfoString(buf, ", dead:");
+			array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead, &offset_elem_desc, NULL);
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_VACUUM)
 	{
 		xl_heap_vacuum *xlrec = (xl_heap_vacuum *) rec;
 
-		appendStringInfo(buf, "nunused %u", xlrec->nunused);
+		appendStringInfo(buf, "nunused: %u", xlrec->nunused);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *nowunused;
+
+			nowunused = (OffsetNumber *) XLogRecGetBlockData(record, 0, NULL);
+
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), xlrec->nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_FREEZE_PAGE)
 	{
 		xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nplans %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u",
 						 xlrec->snapshotConflictHorizon, xlrec->nplans);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			xl_heap_freeze_plan *plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
+			OffsetNumber *offsets = (OffsetNumber *) &plans[xlrec->nplans];
+
+			appendStringInfoString(buf, ", plans:");
+			array_desc(buf,
+					   plans,
+					   sizeof(xl_heap_freeze_plan),
+					   xlrec->nplans,
+					   &plan_elem_desc,
+					   &offsets);
+
+		}
 	}
 	else if (info == XLOG_HEAP2_VISIBLE)
 	{
 		xl_heap_visible *xlrec = (xl_heap_visible *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u flags 0x%02X",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, flags: 0x%02X",
 						 xlrec->snapshotConflictHorizon, xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_MULTI_INSERT)
 	{
 		xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
+		bool		isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
 
-		appendStringInfo(buf, "%d tuples flags 0x%02X", xlrec->ntuples,
+		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
+		appendStringInfoString(buf, ", offsets:");
+		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber), xlrec->ntuples, &offset_elem_desc, NULL);
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off %u: xmax %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -169,13 +265,13 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_new_cid *xlrec = (xl_heap_new_cid *) rec;
 
-		appendStringInfo(buf, "rel %u/%u/%u; tid %u/%u",
+		appendStringInfo(buf, "rel: %u/%u/%u, tid: %u/%u",
 						 xlrec->target_locator.spcOid,
 						 xlrec->target_locator.dbOid,
 						 xlrec->target_locator.relNumber,
 						 ItemPointerGetBlockNumber(&(xlrec->target_tid)),
 						 ItemPointerGetOffsetNumber(&(xlrec->target_tid)));
-		appendStringInfo(buf, "; cmin: %u, cmax: %u, combo: %u",
+		appendStringInfo(buf, ", cmin: %u, cmax: %u, combo: %u",
 						 xlrec->cmin, xlrec->cmax, xlrec->combocid);
 	}
 }
diff --git a/src/backend/access/rmgrdesc/meson.build b/src/backend/access/rmgrdesc/meson.build
index 166cee67b6..f76e87e2d7 100644
--- a/src/backend/access/rmgrdesc/meson.build
+++ b/src/backend/access/rmgrdesc/meson.build
@@ -16,6 +16,7 @@ rmgr_desc_sources = files(
   'nbtdesc.c',
   'relmapdesc.c',
   'replorigindesc.c',
+  'rmgrdesc_utils.c',
   'seqdesc.c',
   'smgrdesc.c',
   'spgdesc.c',
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
new file mode 100644
index 0000000000..2bfd11cb6e
--- /dev/null
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -0,0 +1,82 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.c
+ *		support functions for rmgrdesc
+ *
+ * Portions Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/rmgrdesc/rmgrdesc_utils.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/rmgrdesc_utils.h"
+
+/*
+ * The expected formatting of a desc function for an xlog record is as follows:
+ * member1_name: member1_value, member2_name: member2_value
+ * If the value is a list, please use
+ * member3_name: [ member3_list_value1, member3_list_value2 ]
+ *
+ * The first item appended to the string should not be prepended by any spaces
+ * or comma, however all subsequent appends to the string are responsible for
+ * prepending themselves with a comma followed by a space.
+ *
+ * Arrays should have a space between the opening square bracket and first
+ * element and between the last element and closing brace.
+ *
+ * Flags should be in all caps.
+ *
+ * For lists/arrays of items, the number of those items should be listed at the
+ * beginning with all of the other numbers.
+ *
+ * List punctuation should still be included even if there are 0 items.
+ *
+ * Composite objects in a list should be surrounded with { }.
+ */
+
+void
+array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+		   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+		   void *restrict data)
+{
+	if (count == 0)
+	{
+		appendStringInfoString(buf, " []");
+		return;
+	}
+	appendStringInfo(buf, " [");
+	for (int i = 0; i < count; i++)
+	{
+		if (i > 0)
+			appendStringInfoString(buf, ",");
+		appendStringInfoString(buf, " ");
+
+		elem_desc(buf, (char *) array + elem_size * i, data);
+	}
+	appendStringInfoString(buf, " ]");
+}
+
+void
+offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(OffsetNumber *) offset);
+}
+
+void
+redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data)
+{
+	OffsetNumber *new_offset = (OffsetNumber *) offset;
+
+	appendStringInfo(buf, "%u->%u", new_offset[0], new_offset[1]);
+}
+
+void
+relid_desc(StringInfo buf, void *restrict relid, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(Oid *) relid);
+}
diff --git a/src/bin/pg_waldump/Makefile b/src/bin/pg_waldump/Makefile
index d6459e17c7..61c9de470c 100644
--- a/src/bin/pg_waldump/Makefile
+++ b/src/bin/pg_waldump/Makefile
@@ -18,7 +18,7 @@ OBJS = \
 
 override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
 
-RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c)))
+RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c) $(top_srcdir)/src/backend/access/rmgrdesc/rmgrdesc_utils.c))
 RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
 
 
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
new file mode 100644
index 0000000000..763ae81859
--- /dev/null
+++ b/src/include/access/rmgrdesc_utils.h
@@ -0,0 +1,29 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.h
+ *	  helper utilities for rmgrdesc
+ *
+ * Copyright (c) 2023 PostgreSQL Global Development Group
+ *
+ * src/include/access/rmgrdesc_utils.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef RMGRDESC_UTILS_H_
+#define RMGRDESC_UTILS_H_
+
+#include "storage/off.h"
+#include "access/heapam_xlog.h"
+
+extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+					   void (*elem_desc) (StringInfo buf, void *restrict elem, void *restrict data),
+					   void *restrict data);
+
+extern void offset_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+extern void redirect_elem_desc(StringInfo buf, void *restrict offset, void *restrict data);
+
+extern void relid_desc(StringInfo buf, void *restrict relid, void *restrict data);
+
+
+#endif							/* RMGRDESC_UTILS_H */
-- 
2.37.2

From 88934d500a11e2dc1a20d39a16af1e6fe850a859 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Fri, 7 Apr 2023 14:42:54 -0700
Subject: [PATCH v4] Add rmgr_desc utilities

- Begin to standardize format of rmgr_desc output, adding a new
  rmgr_utils file with comments about expected format.
- Add helper which prints arrays in a standard format and use it in
  heapdesc to print out offset arrays, relid arrays, freeze plan arrays,
  and redirect arrays.

Suggested by Andres Freund

Discussion: https://postgr.es/m/flat/20230109215842.fktuhesvayno6o4g%40awork3.anarazel.de
---
 src/include/access/rmgrdesc_utils.h          |  25 +++
 src/backend/access/rmgrdesc/Makefile         |   1 +
 src/backend/access/rmgrdesc/heapdesc.c       | 159 +++++++++++++++----
 src/backend/access/rmgrdesc/meson.build      |   1 +
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  83 ++++++++++
 src/bin/pg_waldump/Makefile                  |   2 +-
 doc/src/sgml/pgwalinspect.sgml               |  20 +--
 7 files changed, 252 insertions(+), 39 deletions(-)
 create mode 100644 src/include/access/rmgrdesc_utils.h
 create mode 100644 src/backend/access/rmgrdesc/rmgrdesc_utils.c

diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
new file mode 100644
index 000000000..58da418bb
--- /dev/null
+++ b/src/include/access/rmgrdesc_utils.h
@@ -0,0 +1,25 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.h
+ *	  helper utilities for rmgrdesc
+ *
+ * Copyright (c) 2023 PostgreSQL Global Development Group
+ *
+ * src/include/access/rmgrdesc_utils.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef RMGRDESC_UTILS_H_
+#define RMGRDESC_UTILS_H_
+
+#include "storage/off.h"
+#include "access/heapam_xlog.h"
+
+extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
+					   void *data);
+extern void offset_elem_desc(StringInfo buf, void *offset, void *data);
+extern void redirect_elem_desc(StringInfo buf, void *offset, void *data);
+extern void relid_desc(StringInfo buf, void *relid, void *data);
+
+#endif							/* RMGRDESC_UTILS_H */
diff --git a/src/backend/access/rmgrdesc/Makefile b/src/backend/access/rmgrdesc/Makefile
index f88d72fd8..cd95eec37 100644
--- a/src/backend/access/rmgrdesc/Makefile
+++ b/src/backend/access/rmgrdesc/Makefile
@@ -23,6 +23,7 @@ OBJS = \
 	nbtdesc.o \
 	relmapdesc.o \
 	replorigindesc.o \
+	rmgrdesc_utils.o \
 	seqdesc.o \
 	smgrdesc.o \
 	spgdesc.o \
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e821..64427ac56 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -15,20 +15,52 @@
 #include "postgres.h"
 
 #include "access/heapam_xlog.h"
+#include "access/rmgrdesc_utils.h"
 
 static void
 out_infobits(StringInfo buf, uint8 infobits)
 {
+	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
+		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
+		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
+		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
+		(infobits & XLHL_KEYS_UPDATED) == 0)
+		return;
+
+	appendStringInfoString(buf, ", infobits: [");
+
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, "IS_MULTI ");
+		appendStringInfoString(buf, " IS_MULTI");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, "LOCK_ONLY ");
+		appendStringInfoString(buf, ", LOCK_ONLY");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, "EXCL_LOCK ");
+		appendStringInfoString(buf, ", EXCL_LOCK");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, "KEYSHR_LOCK ");
+		appendStringInfoString(buf, ", KEYSHR_LOCK");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, "KEYS_UPDATED ");
+		appendStringInfoString(buf, ", KEYS_UPDATED");
+
+	appendStringInfoString(buf, " ]");
+}
+
+static void
+plan_elem_desc(StringInfo buf, void *plan, void *data)
+{
+	xl_heap_freeze_plan *new_plan = (xl_heap_freeze_plan *) plan;
+	OffsetNumber **offsets = data;
+
+	appendStringInfo(buf, "{ xmax: %u, infomask: %u, infomask2: %u, ntuples: %u",
+					 new_plan->xmax, new_plan->t_infomask,
+					 new_plan->t_infomask2,
+					 new_plan->ntuples);
+
+	appendStringInfoString(buf, ", offsets:");
+	array_desc(buf, *offsets, sizeof(OffsetNumber), new_plan->ntuples,
+			   &offset_elem_desc, NULL);
+
+	*offsets += new_plan->ntuples;
+
+	appendStringInfo(buf, " }");
 }
 
 void
@@ -42,14 +74,15 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_insert *xlrec = (xl_heap_insert *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X", xlrec->offnum,
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+						 xlrec->offnum,
 						 xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_DELETE)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X",
 						 xlrec->offnum,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
@@ -58,12 +91,12 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
@@ -71,39 +104,41 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off %u xmax %u flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
 		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, "; new off %u xmax %u",
+		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
-		int			i;
 
+		appendStringInfoString(buf, "flags: [");
 		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, "cascade ");
+			appendStringInfoString(buf, " CASCADE");
 		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, "restart_seqs ");
-		appendStringInfo(buf, "nrelids %u relids", xlrec->nrelids);
-		for (i = 0; i < xlrec->nrelids; i++)
-			appendStringInfo(buf, " %u", xlrec->relids[i]);
+			appendStringInfoString(buf, ", RESTART_SEQS");
+		appendStringInfoString(buf, " ]");
+
+		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
+		appendStringInfoString(buf, ", relids:");
+		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids, &relid_desc, NULL);
 	}
 	else if (info == XLOG_HEAP_CONFIRM)
 	{
 		xl_heap_confirm *xlrec = (xl_heap_confirm *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 	else if (info == XLOG_HEAP_LOCK)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off %u: xid %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -111,9 +146,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_inplace *xlrec = (xl_heap_inplace *) rec;
 
-		appendStringInfo(buf, "off %u", xlrec->offnum);
+		appendStringInfo(buf, "off: %u", xlrec->offnum);
 	}
 }
+
 void
 heap2_desc(StringInfo buf, XLogReaderState *record)
 {
@@ -125,43 +161,110 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_prune *xlrec = (xl_heap_prune *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nredirected %u ndead %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u",
 						 xlrec->snapshotConflictHorizon,
 						 xlrec->nredirected,
 						 xlrec->ndead);
+
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *end;
+			OffsetNumber *redirected;
+			OffsetNumber *nowdead;
+			OffsetNumber *nowunused;
+			int			nredirected;
+			int			nunused;
+			Size		datalen;
+
+			redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0,
+															  &datalen);
+
+			nredirected = xlrec->nredirected;
+			end = (OffsetNumber *) ((char *) redirected + datalen);
+			nowdead = redirected + (nredirected * 2);
+			nowunused = nowdead + xlrec->ndead;
+			nunused = (end - nowunused);
+			Assert(nunused >= 0);
+
+			appendStringInfo(buf, ", nunused: %u", nunused);
+
+			appendStringInfoString(buf, ", redirected:");
+			array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
+					   nredirected * 2, &redirect_elem_desc, NULL);
+			appendStringInfoString(buf, ", dead:");
+			array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead,
+					   &offset_elem_desc, NULL);
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
+					   &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_VACUUM)
 	{
 		xl_heap_vacuum *xlrec = (xl_heap_vacuum *) rec;
 
-		appendStringInfo(buf, "nunused %u", xlrec->nunused);
+		appendStringInfo(buf, "nunused: %u", xlrec->nunused);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			OffsetNumber *nowunused;
+
+			nowunused = (OffsetNumber *) XLogRecGetBlockData(record, 0, NULL);
+
+			appendStringInfoString(buf, ", unused:");
+			array_desc(buf, nowunused, sizeof(OffsetNumber), xlrec->nunused, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_FREEZE_PAGE)
 	{
 		xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u nplans %u",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u",
 						 xlrec->snapshotConflictHorizon, xlrec->nplans);
+
+		if (!XLogRecHasBlockImage(record, 0))
+		{
+			xl_heap_freeze_plan *plans;
+			OffsetNumber *offsets;
+
+			plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
+			offsets = (OffsetNumber *) &plans[xlrec->nplans];
+			appendStringInfoString(buf, ", plans:");
+			array_desc(buf,
+					   plans,
+					   sizeof(xl_heap_freeze_plan),
+					   xlrec->nplans,
+					   &plan_elem_desc,
+					   &offsets);
+
+		}
 	}
 	else if (info == XLOG_HEAP2_VISIBLE)
 	{
 		xl_heap_visible *xlrec = (xl_heap_visible *) rec;
 
-		appendStringInfo(buf, "snapshotConflictHorizon %u flags 0x%02X",
+		appendStringInfo(buf, "snapshotConflictHorizon: %u, flags: 0x%02X",
 						 xlrec->snapshotConflictHorizon, xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_MULTI_INSERT)
 	{
 		xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
+		bool		isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
 
-		appendStringInfo(buf, "%d tuples flags 0x%02X", xlrec->ntuples,
+		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
+
+		appendStringInfoString(buf, ", offsets:");
+		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber),
+					   xlrec->ntuples, &offset_elem_desc, NULL);
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off %u: xmax %u: flags 0x%02X ",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
 		out_infobits(buf, xlrec->infobits_set);
 	}
@@ -169,13 +272,13 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_new_cid *xlrec = (xl_heap_new_cid *) rec;
 
-		appendStringInfo(buf, "rel %u/%u/%u; tid %u/%u",
+		appendStringInfo(buf, "rel: %u/%u/%u, tid: %u/%u",
 						 xlrec->target_locator.spcOid,
 						 xlrec->target_locator.dbOid,
 						 xlrec->target_locator.relNumber,
 						 ItemPointerGetBlockNumber(&(xlrec->target_tid)),
 						 ItemPointerGetOffsetNumber(&(xlrec->target_tid)));
-		appendStringInfo(buf, "; cmin: %u, cmax: %u, combo: %u",
+		appendStringInfo(buf, ", cmin: %u, cmax: %u, combo: %u",
 						 xlrec->cmin, xlrec->cmax, xlrec->combocid);
 	}
 }
diff --git a/src/backend/access/rmgrdesc/meson.build b/src/backend/access/rmgrdesc/meson.build
index 166cee67b..f76e87e2d 100644
--- a/src/backend/access/rmgrdesc/meson.build
+++ b/src/backend/access/rmgrdesc/meson.build
@@ -16,6 +16,7 @@ rmgr_desc_sources = files(
   'nbtdesc.c',
   'relmapdesc.c',
   'replorigindesc.c',
+  'rmgrdesc_utils.c',
   'seqdesc.c',
   'smgrdesc.c',
   'spgdesc.c',
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
new file mode 100644
index 000000000..2b3c1887d
--- /dev/null
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -0,0 +1,83 @@
+/*-------------------------------------------------------------------------
+ *
+ * rmgrdesc_utils.c
+ *		support functions for rmgrdesc
+ *
+ * Portions Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/rmgrdesc/rmgrdesc_utils.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/rmgrdesc_utils.h"
+
+/*
+ * Guidelines for formatting desc functions:
+ *
+ * member1_name: member1_value, member2_name: member2_value
+ *
+ * If the value is a list, please use:
+ *
+ * member3_name: [ member3_list_value1, member3_list_value2 ]
+ *
+ * The first item appended to the string should not be prepended by any spaces
+ * or comma, however all subsequent appends to the string are responsible for
+ * prepending themselves with a comma followed by a space.
+ *
+ * Arrays should have a space between the opening square bracket and first
+ * element and between the last element and closing brace.
+ *
+ * Flags should be in ALL CAPS.
+ *
+ * For lists/arrays of items, the number of those items should be listed at
+ * the beginning with all of the other numbers.
+ *
+ * List punctuation should still be included even if there are 0 items.
+ *
+ * Composite objects in a list should be surrounded with { }.
+ */
+void
+array_desc(StringInfo buf, void *array, size_t elem_size, int count,
+		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
+		   void *data)
+{
+	if (count == 0)
+	{
+		appendStringInfoString(buf, " []");
+		return;
+	}
+	appendStringInfo(buf, " [");
+	for (int i = 0; i < count; i++)
+	{
+		if (i > 0)
+			appendStringInfoString(buf, ",");
+		appendStringInfoString(buf, " ");
+
+		elem_desc(buf, (char *) array + elem_size * i, data);
+	}
+	appendStringInfoString(buf, " ]");
+}
+
+void
+offset_elem_desc(StringInfo buf, void *offset, void *data)
+{
+	appendStringInfo(buf, "%u", *(OffsetNumber *) offset);
+}
+
+void
+redirect_elem_desc(StringInfo buf, void *offset, void *data)
+{
+	OffsetNumber *new_offset = (OffsetNumber *) offset;
+
+	appendStringInfo(buf, "%u->%u", new_offset[0], new_offset[1]);
+}
+
+void
+relid_desc(StringInfo buf, void *relid, void *data)
+{
+	appendStringInfo(buf, "%u", *(Oid *) relid);
+}
diff --git a/src/bin/pg_waldump/Makefile b/src/bin/pg_waldump/Makefile
index d6459e17c..0ecf58203 100644
--- a/src/bin/pg_waldump/Makefile
+++ b/src/bin/pg_waldump/Makefile
@@ -18,7 +18,7 @@ OBJS = \
 
 override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
 
-RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c)))
+RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc*.c)))
 RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
 
 
diff --git a/doc/src/sgml/pgwalinspect.sgml b/doc/src/sgml/pgwalinspect.sgml
index d9ed8f0a9..0928717ba 100644
--- a/doc/src/sgml/pgwalinspect.sgml
+++ b/doc/src/sgml/pgwalinspect.sgml
@@ -71,19 +71,19 @@
       after the <replaceable>in_lsn</replaceable> argument.  For
       example:
 <screen>
-postgres=# SELECT * FROM pg_get_wal_record_info('0/1E826E98');
--[ RECORD 1 ]----+----------------------------------------------------
-start_lsn        | 0/1E826F20
-end_lsn          | 0/1E826F60
-prev_lsn         | 0/1E826C80
+postgres=# SELECT * FROM pg_get_wal_record_info(''0/E84F5E8'');
+-[ RECORD 1 ]----+--------------------------------------------------
+start_lsn        | 0/E84F5E8
+end_lsn          | 0/E84F620
+prev_lsn         | 0/E84F5A8
 xid              | 0
 resource_manager | Heap2
-record_type      | PRUNE
-record_length    | 58
-main_data_length | 8
+record_type      | VACUUM
+record_length    | 50
+main_data_length | 2
 fpi_length       | 0
-description      | snapshotConflictHorizon 33748 nredirected 0 ndead 2
-block_ref        | blkref #0: rel 1663/5/60221 fork main blk 2
+description      | nunused: 1, unused: [ 22 ]
+block_ref        | blkref #0: rel 1663/16389/20884 fork main blk 126
 </screen>
      </para>
      <para>
-- 
2.34.1

From 4f502b2513ba79d738e7ed87aaf7d18ed2a2e30f Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Mon, 13 Mar 2023 18:15:17 -0400
Subject: [PATCH v4 2/2] Add detail to some btree xlog record descs

Suggested by Peter Geoghegan

Discussion: https://postgr.es/m/flat/20230109215842.fktuhesvayno6o4g%40awork3.anarazel.de
---
 src/backend/access/rmgrdesc/nbtdesc.c        | 84 +++++++++++++++++---
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  6 ++
 src/include/access/rmgrdesc_utils.h          |  2 +
 3 files changed, 81 insertions(+), 11 deletions(-)

diff --git a/src/backend/access/rmgrdesc/nbtdesc.c b/src/backend/access/rmgrdesc/nbtdesc.c
index c5dc543a0f..9ffece109d 100644
--- a/src/backend/access/rmgrdesc/nbtdesc.c
+++ b/src/backend/access/rmgrdesc/nbtdesc.c
@@ -15,6 +15,58 @@
 #include "postgres.h"
 
 #include "access/nbtxlog.h"
+#include "access/rmgrdesc_utils.h"
+
+static void btree_del_desc(StringInfo buf, char *block_data, uint16 ndeleted,
+						   uint16 nupdated);
+static void btree_update_elem_desc(StringInfo buf, void *restrict update, void
+								   *restrict data);
+
+static void
+btree_del_desc(StringInfo buf, char *block_data, uint16 ndeleted, uint16 nupdated)
+{
+	OffsetNumber *updatedoffsets;
+	xl_btree_update *updates;
+	OffsetNumber *data = (OffsetNumber *) block_data;
+
+	appendStringInfoString(buf, ", deleted:");
+	array_desc(buf, data, sizeof(OffsetNumber), ndeleted, &offset_elem_desc, NULL);
+
+	appendStringInfoString(buf, ", updated:");
+	array_desc(buf, data, sizeof(OffsetNumber), nupdated, &offset_elem_desc, NULL);
+
+	if (nupdated <= 0)
+		return;
+
+	updatedoffsets = (OffsetNumber *)
+		((char *) data + ndeleted * sizeof(OffsetNumber));
+	updates = (xl_btree_update *) ((char *) updatedoffsets +
+								   nupdated *
+								   sizeof(OffsetNumber));
+
+	appendStringInfoString(buf, ", updates:");
+	array_desc(buf, updates, sizeof(xl_btree_update),
+			   nupdated, &btree_update_elem_desc,
+			   &updatedoffsets);
+}
+
+static void
+btree_update_elem_desc(StringInfo buf, void *restrict update, void *restrict data)
+{
+	xl_btree_update *new_update = (xl_btree_update *) update;
+	OffsetNumber *updated_offset = *((OffsetNumber **) data);
+
+	appendStringInfo(buf, "{ updated offset: %u, ndeleted tids: %u", *updated_offset, new_update->ndeletedtids);
+
+	appendStringInfoString(buf, ", deleted tids:");
+
+	array_desc(buf, (char *) new_update + SizeOfBtreeUpdate,
+			   sizeof(uint16), new_update->ndeletedtids, &uint16_elem_desc, NULL);
+
+	updated_offset++;
+
+	appendStringInfo(buf, " }");
+}
 
 void
 btree_desc(StringInfo buf, XLogReaderState *record)
@@ -31,7 +83,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_insert *xlrec = (xl_btree_insert *) rec;
 
-				appendStringInfo(buf, "off %u", xlrec->offnum);
+				appendStringInfo(buf, "off: %u", xlrec->offnum);
 				break;
 			}
 		case XLOG_BTREE_SPLIT_L:
@@ -39,7 +91,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_split *xlrec = (xl_btree_split *) rec;
 
-				appendStringInfo(buf, "level %u, firstrightoff %d, newitemoff %d, postingoff %d",
+				appendStringInfo(buf, "level: %u, firstrightoff: %d, newitemoff: %d, postingoff: %d",
 								 xlrec->level, xlrec->firstrightoff,
 								 xlrec->newitemoff, xlrec->postingoff);
 				break;
@@ -48,31 +100,41 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_dedup *xlrec = (xl_btree_dedup *) rec;
 
-				appendStringInfo(buf, "nintervals %u", xlrec->nintervals);
+				appendStringInfo(buf, "nintervals: %u", xlrec->nintervals);
 				break;
 			}
 		case XLOG_BTREE_VACUUM:
 			{
 				xl_btree_vacuum *xlrec = (xl_btree_vacuum *) rec;
 
-				appendStringInfo(buf, "ndeleted %u; nupdated %u",
+				appendStringInfo(buf, "ndeleted: %u, nupdated: %u",
 								 xlrec->ndeleted, xlrec->nupdated);
+
+				if (!XLogRecHasBlockImage(record, 0))
+					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+								   xlrec->ndeleted, xlrec->nupdated);
+
 				break;
 			}
 		case XLOG_BTREE_DELETE:
 			{
 				xl_btree_delete *xlrec = (xl_btree_delete *) rec;
 
-				appendStringInfo(buf, "snapshotConflictHorizon %u; ndeleted %u; nupdated %u",
+				appendStringInfo(buf, "snapshotConflictHorizon: %u, ndeleted: %u, nupdated: %u",
 								 xlrec->snapshotConflictHorizon,
 								 xlrec->ndeleted, xlrec->nupdated);
+
+				if (!XLogRecHasBlockImage(record, 0))
+					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+								   xlrec->ndeleted, xlrec->nupdated);
+
 				break;
 			}
 		case XLOG_BTREE_MARK_PAGE_HALFDEAD:
 			{
 				xl_btree_mark_page_halfdead *xlrec = (xl_btree_mark_page_halfdead *) rec;
 
-				appendStringInfo(buf, "topparent %u; leaf %u; left %u; right %u",
+				appendStringInfo(buf, "topparent: %u; leaf: %u; left: %u; right: %u",
 								 xlrec->topparent, xlrec->leafblk, xlrec->leftblk, xlrec->rightblk);
 				break;
 			}
@@ -81,11 +143,11 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_unlink_page *xlrec = (xl_btree_unlink_page *) rec;
 
-				appendStringInfo(buf, "left %u; right %u; level %u; safexid %u:%u; ",
+				appendStringInfo(buf, "left: %u; right: %u; level: %u; safexid: %u:%u; ",
 								 xlrec->leftsib, xlrec->rightsib, xlrec->level,
 								 EpochFromFullTransactionId(xlrec->safexid),
 								 XidFromFullTransactionId(xlrec->safexid));
-				appendStringInfo(buf, "leafleft %u; leafright %u; leaftopparent %u",
+				appendStringInfo(buf, "leafleft: %u; leafright: %u; leaftopparent: %u",
 								 xlrec->leafleftsib, xlrec->leafrightsib,
 								 xlrec->leaftopparent);
 				break;
@@ -94,14 +156,14 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_newroot *xlrec = (xl_btree_newroot *) rec;
 
-				appendStringInfo(buf, "lev %u", xlrec->level);
+				appendStringInfo(buf, "lev: %u", xlrec->level);
 				break;
 			}
 		case XLOG_BTREE_REUSE_PAGE:
 			{
 				xl_btree_reuse_page *xlrec = (xl_btree_reuse_page *) rec;
 
-				appendStringInfo(buf, "rel %u/%u/%u; snapshotConflictHorizon %u:%u",
+				appendStringInfo(buf, "rel: %u/%u/%u, snapshotConflictHorizon: %u:%u",
 								 xlrec->locator.spcOid, xlrec->locator.dbOid,
 								 xlrec->locator.relNumber,
 								 EpochFromFullTransactionId(xlrec->snapshotConflictHorizon),
@@ -114,7 +176,7 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 
 				xlrec = (xl_btree_metadata *) XLogRecGetBlockData(record, 0,
 																  NULL);
-				appendStringInfo(buf, "last_cleanup_num_delpages %u",
+				appendStringInfo(buf, "last_cleanup_num_delpages: %u",
 								 xlrec->last_cleanup_num_delpages);
 				break;
 			}
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 2bfd11cb6e..1268d6131e 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -80,3 +80,9 @@ relid_desc(StringInfo buf, void *restrict relid, void *restrict data)
 {
 	appendStringInfo(buf, "%u", *(Oid *) relid);
 }
+
+void
+uint16_elem_desc(StringInfo buf, void *restrict value, void *restrict data)
+{
+	appendStringInfo(buf, "%u", *(uint16 *) value);
+}
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 763ae81859..ce24accc3b 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -25,5 +25,7 @@ extern void redirect_elem_desc(StringInfo buf, void *restrict offset, void *rest
 
 extern void relid_desc(StringInfo buf, void *restrict relid, void *restrict data);
 
+extern void uint16_elem_desc(StringInfo buf, void *restrict value, void *restrict data);
+
 
 #endif							/* RMGRDESC_UTILS_H */
-- 
2.37.2

From 44bfa575f5f28d1a8093e02b4a7993c1368cbeb5 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sat, 8 Apr 2023 18:59:09 -0700
Subject: [PATCH v1] Fix WAL description of posting list updates.

---
 src/include/access/rmgrdesc_utils.h          |  41 ++++++-
 src/backend/access/rmgrdesc/heapdesc.c       |   2 +-
 src/backend/access/rmgrdesc/nbtdesc.c        | 121 ++++++++++---------
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  43 +------
 doc/src/sgml/pgwalinspect.sgml               |  34 +++---
 5 files changed, 123 insertions(+), 118 deletions(-)

diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 13552d6f3..16916e3e8 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,12 +12,49 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
+/*
+ * Guidelines for rmgr descriptor routine authors:
+ *
+ * The goal of these guidelines is to avoid gratuitous inconsistencies across
+ * each rmgr, and to allow users to parse desc output strings without too much
+ * difficulty.  This is not an API specification or an interchange format.
+ * (Only heapam and nbtree desc routines follow these guidelines at present,
+ * in any case.)
+ *
+ * Record descriptions are similar to JSON style key/value objects.  However,
+ * there is no explicit "string" type/string escaping.  Top-level { } brackets
+ * should be omitted.  For example:
+ *
+ * snapshotConflictHorizon: 0, flags: 0x03
+ *
+ * Record descriptions may contain variable-length arrays.  For example:
+ *
+ * nunused: 5, unused: [1, 2, 3, 4, 5]
+ *
+ * Nested objects are supported via { } brackets.  They generally appear
+ * inside variable-length arrays.  For example:
+ *
+ * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+ *
+ * Try to output things in an order that faithfully represents the order of
+ * things in the physical WAL record struct.  It's a good idea if the number
+ * of items in the array appears before the array.
+ *
+ * It's okay for individual WAL record types to invent their own conventions.
+ * For example, heapam's PRUNE records output the follow representation of
+ * redirects:
+ *
+ * ... redirected: [39->46], ...
+ *
+ * Arguably the PRUNE desc routine should be using object notation instead.
+ * This ad-hoc representation of redirects has the advantage of being terse in
+ * a context where that might matter a lot.
+ */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
 extern void offset_elem_desc(StringInfo buf, void *offset, void *data);
 extern void redirect_elem_desc(StringInfo buf, void *offset, void *data);
-extern void relid_desc(StringInfo buf, void *relid, void *data);
-extern void uint16_elem_desc(StringInfo buf, void *value, void *data);
+extern void oid_elem_desc(StringInfo buf, void *relid, void *data);
 
 #endif							/* RMGRDESC_UTILS_H */
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 6dfd7d7d1..3bd083875 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -127,7 +127,7 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
 		appendStringInfoString(buf, ", relids:");
 		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids,
-				   &relid_desc, NULL);
+				   &oid_elem_desc, NULL);
 	}
 	else if (info == XLOG_HEAP_CONFIRM)
 	{
diff --git a/src/backend/access/rmgrdesc/nbtdesc.c b/src/backend/access/rmgrdesc/nbtdesc.c
index 6bc043265..6edb02a0b 100644
--- a/src/backend/access/rmgrdesc/nbtdesc.c
+++ b/src/backend/access/rmgrdesc/nbtdesc.c
@@ -17,59 +17,8 @@
 #include "access/nbtxlog.h"
 #include "access/rmgrdesc_utils.h"
 
-static void btree_del_desc(StringInfo buf, char *block_data, uint16 ndeleted,
-						   uint16 nupdated);
-static void btree_update_elem_desc(StringInfo buf, void *update, void *data);
-
-static void
-btree_del_desc(StringInfo buf, char *block_data, uint16 ndeleted,
-			   uint16 nupdated)
-{
-	OffsetNumber *updatedoffsets;
-	xl_btree_update *updates;
-	OffsetNumber *data = (OffsetNumber *) block_data;
-
-	appendStringInfoString(buf, ", deleted:");
-	array_desc(buf, data, sizeof(OffsetNumber), ndeleted,
-			   &offset_elem_desc, NULL);
-
-	appendStringInfoString(buf, ", updated:");
-	array_desc(buf, data, sizeof(OffsetNumber), nupdated,
-			   &offset_elem_desc, NULL);
-
-	if (nupdated <= 0)
-		return;
-
-	updatedoffsets = (OffsetNumber *)
-		((char *) data + ndeleted * sizeof(OffsetNumber));
-	updates = (xl_btree_update *) ((char *) updatedoffsets +
-								   nupdated *
-								   sizeof(OffsetNumber));
-
-	appendStringInfoString(buf, ", updates:");
-	array_desc(buf, updates, sizeof(xl_btree_update),
-			   nupdated, &btree_update_elem_desc,
-			   &updatedoffsets);
-}
-
-static void
-btree_update_elem_desc(StringInfo buf, void *update, void *data)
-{
-	xl_btree_update *new_update = (xl_btree_update *) update;
-	OffsetNumber *updated_offset = *((OffsetNumber **) data);
-
-	appendStringInfo(buf, "{ updated offset: %u, ndeleted tids: %u",
-					 *updated_offset, new_update->ndeletedtids);
-
-	appendStringInfoString(buf, ", deleted tids:");
-
-	array_desc(buf, (char *) new_update + SizeOfBtreeUpdate, sizeof(uint16),
-			   new_update->ndeletedtids, &uint16_elem_desc, NULL);
-
-	updated_offset++;
-
-	appendStringInfo(buf, " }");
-}
+static void delvacuum_desc(StringInfo buf, char *block_data,
+						   uint16 ndeleted, uint16 nupdated);
 
 void
 btree_desc(StringInfo buf, XLogReaderState *record)
@@ -114,9 +63,8 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 								 xlrec->ndeleted, xlrec->nupdated);
 
 				if (!XLogRecHasBlockImage(record, 0))
-					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+					delvacuum_desc(buf, XLogRecGetBlockData(record, 0, NULL),
 								   xlrec->ndeleted, xlrec->nupdated);
-
 				break;
 			}
 		case XLOG_BTREE_DELETE:
@@ -128,16 +76,15 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 								 xlrec->ndeleted, xlrec->nupdated);
 
 				if (!XLogRecHasBlockImage(record, 0))
-					btree_del_desc(buf, XLogRecGetBlockData(record, 0, NULL),
+					delvacuum_desc(buf, XLogRecGetBlockData(record, 0, NULL),
 								   xlrec->ndeleted, xlrec->nupdated);
-
 				break;
 			}
 		case XLOG_BTREE_MARK_PAGE_HALFDEAD:
 			{
 				xl_btree_mark_page_halfdead *xlrec = (xl_btree_mark_page_halfdead *) rec;
 
-				appendStringInfo(buf, "topparent: %u; leaf: %u; left: %u; right: %u",
+				appendStringInfo(buf, "topparent: %u, leaf: %u, left: %u, right: %u",
 								 xlrec->topparent, xlrec->leafblk, xlrec->leftblk, xlrec->rightblk);
 				break;
 			}
@@ -146,11 +93,11 @@ btree_desc(StringInfo buf, XLogReaderState *record)
 			{
 				xl_btree_unlink_page *xlrec = (xl_btree_unlink_page *) rec;
 
-				appendStringInfo(buf, "left: %u; right: %u; level: %u; safexid: %u:%u; ",
+				appendStringInfo(buf, "left: %u, right: %u, level: %u, safexid: %u:%u, ",
 								 xlrec->leftsib, xlrec->rightsib, xlrec->level,
 								 EpochFromFullTransactionId(xlrec->safexid),
 								 XidFromFullTransactionId(xlrec->safexid));
-				appendStringInfo(buf, "leafleft: %u; leafright: %u; leaftopparent: %u",
+				appendStringInfo(buf, "leafleft: %u, leafright: %u, leaftopparent: %u",
 								 xlrec->leafleftsib, xlrec->leafrightsib,
 								 xlrec->leaftopparent);
 				break;
@@ -242,3 +189,57 @@ btree_identify(uint8 info)
 
 	return id;
 }
+
+static void
+delvacuum_desc(StringInfo buf, char *block_data,
+			   uint16 ndeleted, uint16 nupdated)
+{
+	OffsetNumber *deletedoffsets;
+	OffsetNumber *updatedoffsets;
+	xl_btree_update *updates;
+
+	/* Output deleted page offset number array */
+	appendStringInfoString(buf, ", deleted:");
+	deletedoffsets = (OffsetNumber *) block_data;
+	array_desc(buf, deletedoffsets, sizeof(OffsetNumber), ndeleted,
+			   &offset_elem_desc, NULL);
+
+	/*
+	 * Output updates as an array of "update objects", where each element
+	 * contains a page offset number from updated array.  (This is not the
+	 * most literal representation of the underlying physical data structure
+	 * that we could use.  Readability seems more important here.)
+	 */
+	appendStringInfoString(buf, ", updated: [");
+	updatedoffsets = (OffsetNumber *) (block_data + ndeleted *
+									   sizeof(OffsetNumber));
+	updates = (xl_btree_update *) ((char *) updatedoffsets +
+								   nupdated *
+								   sizeof(OffsetNumber));
+	for (int i = 0; i < nupdated; i++)
+	{
+		OffsetNumber off = updatedoffsets[i];
+
+		appendStringInfo(buf, "{ off: %u, nptids: %u, ptids: [",
+						 off, updates->ndeletedtids);
+		Assert(updates->ndeletedtids > 0);
+		for (int p = 0; p < updates->ndeletedtids; p++)
+		{
+			uint16 *ptid;
+
+			ptid = (uint16 *) ((char *) updates + SizeOfBtreeUpdate) + p;
+			appendStringInfo(buf, "%u", *ptid);
+
+			if (p < updates->ndeletedtids - 1)
+				appendStringInfoString(buf, ", ");
+		}
+		appendStringInfoString(buf, "] }");
+		if (i < nupdated - 1)
+			appendStringInfoString(buf, ", ");
+
+		updates = (xl_btree_update *)
+			((char *) updates + SizeOfBtreeUpdate +
+			 updates->ndeletedtids * sizeof(uint16));
+	}
+	appendStringInfoString(buf, "]");
+}
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index c95a41a25..90051f0df 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,31 +16,6 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
-/*
- * Guidelines for formatting desc functions:
- *
- * member1_name: member1_value, member2_name: member2_value
- *
- * If the value is a list, please use:
- *
- * member3_name: [ member3_list_value1, member3_list_value2 ]
- *
- * The first item appended to the string should not be prepended by any spaces
- * or comma, however all subsequent appends to the string are responsible for
- * prepending themselves with a comma followed by a space.
- *
- * Arrays should have a space between the opening square bracket and first
- * element and between the last element and closing brace.
- *
- * Flags should be in ALL CAPS.
- *
- * For lists/arrays of items, the number of those items should be listed at
- * the beginning with all of the other numbers.
- *
- * List punctuation should still be included even if there are 0 items.
- *
- * Composite objects in a list should be surrounded with { }.
- */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
@@ -51,16 +26,14 @@ array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		appendStringInfoString(buf, " []");
 		return;
 	}
-	appendStringInfo(buf, " [");
+	appendStringInfoString(buf, " [");
 	for (int i = 0; i < count; i++)
 	{
-		if (i > 0)
-			appendStringInfoString(buf, ",");
-		appendStringInfoString(buf, " ");
-
 		elem_desc(buf, (char *) array + elem_size * i, data);
+		if (i < count - 1)
+			appendStringInfoString(buf, ", ");
 	}
-	appendStringInfoString(buf, " ]");
+	appendStringInfoString(buf, "]");
 }
 
 void
@@ -78,13 +51,7 @@ redirect_elem_desc(StringInfo buf, void *offset, void *data)
 }
 
 void
-relid_desc(StringInfo buf, void *relid, void *data)
+oid_elem_desc(StringInfo buf, void *relid, void *data)
 {
 	appendStringInfo(buf, "%u", *(Oid *) relid);
 }
-
-void
-uint16_elem_desc(StringInfo buf, void *value, void *data)
-{
-	appendStringInfo(buf, "%u", *(uint16 *) value);
-}
diff --git a/doc/src/sgml/pgwalinspect.sgml b/doc/src/sgml/pgwalinspect.sgml
index b3712be00..a1a4422fb 100644
--- a/doc/src/sgml/pgwalinspect.sgml
+++ b/doc/src/sgml/pgwalinspect.sgml
@@ -71,19 +71,19 @@
       after the <replaceable>in_lsn</replaceable> argument.  For
       example:
 <screen>
-postgres=# SELECT * FROM pg_get_wal_record_info('0/E84F5E8');
--[ RECORD 1 ]----+--------------------------------------------------
-start_lsn        | 0/E84F5E8
-end_lsn          | 0/E84F620
-prev_lsn         | 0/E84F5A8
+postgres=# SELECT * FROM pg_get_wal_record_info('0/E419E28');
+-[ RECORD 1 ]----+-------------------------------------------------
+start_lsn        | 0/E419E28
+end_lsn          | 0/E419E68
+prev_lsn         | 0/E419D78
 xid              | 0
 resource_manager | Heap2
 record_type      | VACUUM
-record_length    | 50
+record_length    | 58
 main_data_length | 2
 fpi_length       | 0
-description      | nunused: 1, unused: [ 22 ]
-block_ref        | blkref #0: rel 1663/16389/20884 fork main blk 126
+description      | nunused: 5, unused: [1, 2, 3, 4, 5]
+block_ref        | blkref #0: rel 1663/16385/1249 fork main blk 364
 </screen>
      </para>
      <para>
@@ -144,18 +144,18 @@ block_ref        |
       references.  Returns one row per block reference per WAL record.
       For example:
 <screen>
-postgres=# SELECT * FROM pg_get_wal_block_info('0/10E9D80', '0/10E9DC0');
+postgres=# SELECT * FROM pg_get_wal_block_info('0/1230278', '0/12302B8');
 -[ RECORD 1 ]-----+-----------------------------------
-start_lsn         | 0/10E9D80
-end_lsn           | 0/10E9DC0
-prev_lsn          | 0/10E9860
+start_lsn         | 0/1230278
+end_lsn           | 0/12302B8
+prev_lsn          | 0/122FD40
 block_id          | 0
 reltablespace     | 1663
 reldatabase       | 1
-relfilenode       | 2690
+relfilenode       | 2658
 relforknumber     | 0
-relblocknumber    | 5
-xid               | 117
+relblocknumber    | 11
+xid               | 341
 resource_manager  | Btree
 record_type       | INSERT_LEAF
 record_length     | 64
@@ -163,8 +163,8 @@ main_data_length  | 2
 block_data_length | 16
 block_fpi_length  | 0
 block_fpi_info    |
-description       | off 14
-block_data        | \x00005400020010001407000000000000
+description       | off: 46
+block_data        | \x00002a00070010402630000070696400
 block_fpi_data    |
 </screen>
      </para>
-- 
2.40.0

From 06865859f3c5da8d735f52719ec0ac0632322be1 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sun, 9 Apr 2023 18:14:27 -0700
Subject: [PATCH v1 1/2] Fix heapdesc infomask array output.

---
 src/include/access/rmgrdesc_utils.h          |  38 +++++++
 src/backend/access/rmgrdesc/heapdesc.c       | 105 +++++++++++++------
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  20 ----
 3 files changed, 112 insertions(+), 51 deletions(-)

diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 00e614649..16916e3e8 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,6 +12,44 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
+/*
+ * Guidelines for rmgr descriptor routine authors:
+ *
+ * The goal of these guidelines is to avoid gratuitous inconsistencies across
+ * each rmgr, and to allow users to parse desc output strings without too much
+ * difficulty.  This is not an API specification or an interchange format.
+ * (Only heapam and nbtree desc routines follow these guidelines at present,
+ * in any case.)
+ *
+ * Record descriptions are similar to JSON style key/value objects.  However,
+ * there is no explicit "string" type/string escaping.  Top-level { } brackets
+ * should be omitted.  For example:
+ *
+ * snapshotConflictHorizon: 0, flags: 0x03
+ *
+ * Record descriptions may contain variable-length arrays.  For example:
+ *
+ * nunused: 5, unused: [1, 2, 3, 4, 5]
+ *
+ * Nested objects are supported via { } brackets.  They generally appear
+ * inside variable-length arrays.  For example:
+ *
+ * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+ *
+ * Try to output things in an order that faithfully represents the order of
+ * things in the physical WAL record struct.  It's a good idea if the number
+ * of items in the array appears before the array.
+ *
+ * It's okay for individual WAL record types to invent their own conventions.
+ * For example, heapam's PRUNE records output the follow representation of
+ * redirects:
+ *
+ * ... redirected: [39->46], ...
+ *
+ * Arguably the PRUNE desc routine should be using object notation instead.
+ * This ad-hoc representation of redirects has the advantage of being terse in
+ * a context where that might matter a lot.
+ */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 3bd083875..a64d14c2c 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -18,29 +18,75 @@
 #include "access/rmgrdesc_utils.h"
 
 static void
-out_infobits(StringInfo buf, uint8 infobits)
+infobits_desc(StringInfo buf, uint8 infobits, const char *keyname)
 {
-	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
-		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
-		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
-		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
-		(infobits & XLHL_KEYS_UPDATED) == 0)
-		return;
+	bool		first = true;
 
-	appendStringInfoString(buf, ", infobits: [");
+	appendStringInfo(buf, "%s: [", keyname);
 
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, " IS_MULTI");
+	{
+		appendStringInfoString(buf, "IS_MULTI");
+		first = false;
+	}
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, ", LOCK_ONLY");
+	{
+		if (first)
+			appendStringInfoString(buf, "LOCK_ONLY");
+		else
+			appendStringInfoString(buf, ", LOCK_ONLY");
+		first = false;
+	}
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, ", EXCL_LOCK");
+	{
+		if (first)
+			appendStringInfoString(buf, "EXCL_LOCK");
+		else
+			appendStringInfoString(buf, ", EXCL_LOCK");
+		first = false;
+	}
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, ", KEYSHR_LOCK");
+	{
+		if (first)
+			appendStringInfoString(buf, "KEYSHR_LOCK");
+		else
+			appendStringInfoString(buf, ", KEYSHR_LOCK");
+		first = false;
+	}
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, ", KEYS_UPDATED");
+	{
+		if (first)
+			appendStringInfoString(buf, "KEYS_UPDATED");
+		else
+			appendStringInfoString(buf, ", KEYS_UPDATED");
+		first = false;
+	}
 
-	appendStringInfoString(buf, " ]");
+	appendStringInfoString(buf, "]");
+}
+
+static void
+truncate_flags_desc(StringInfo buf, uint8 flags)
+{
+	bool		first = true;
+
+	appendStringInfoString(buf, "flags: [");
+
+	if (flags & XLH_TRUNCATE_CASCADE)
+	{
+		appendStringInfoString(buf, "CASCADE");
+		first = false;
+	}
+	if (flags & XLH_TRUNCATE_RESTART_SEQS)
+	{
+		if (first)
+			appendStringInfoString(buf, "RESTART_SEQS");
+		else
+			appendStringInfoString(buf, ", RESTART_SEQS");
+		first = false;
+	}
+
+	appendStringInfoString(buf, "]");
 }
 
 static void
@@ -82,20 +128,20 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X, ",
 						 xlrec->offnum,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
 		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
@@ -104,11 +150,11 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
 		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
@@ -117,12 +163,7 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
 
-		appendStringInfoString(buf, "flags: [");
-		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, " CASCADE");
-		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, ", RESTART_SEQS");
-		appendStringInfoString(buf, " ]");
+		truncate_flags_desc(buf, xlrec->flags);
 
 		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
 		appendStringInfoString(buf, ", relids:");
@@ -139,9 +180,9 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X, ",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP_INPLACE)
 	{
@@ -230,7 +271,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 			OffsetNumber *offsets;
 
 			plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
-			offsets = (OffsetNumber *) &plans[xlrec->nplans];
+			offsets = (OffsetNumber *) ((char *) plans +
+										(xlrec->nplans *
+										 sizeof(xl_heap_freeze_plan)));
 			appendStringInfoString(buf, ", plans:");
 			array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
 					   &plan_elem_desc, &offsets);
@@ -260,9 +303,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP2_NEW_CID)
 	{
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 3d16b1fcb..90051f0df 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,26 +16,6 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
-/*
- * Guidelines for formatting desc functions:
- *
- * member1_name: member1_value, member2_name: member2_value
- *
- * If the value is a list, please use:
- *
- * member3_name: [ member3_list_value1, member3_list_value2 ]
- *
- * The first item appended to the string should not be prepended by any spaces
- * or comma, however all subsequent appends to the string are responsible for
- * prepending themselves with a comma followed by a space.
- *
- * Flags should be in ALL CAPS.
- *
- * For lists/arrays of items, the number of those items should be listed at
- * the beginning with all of the other numbers.
- *
- * Composite objects in a list should be surrounded with { }.
- */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
-- 
2.40.0

From 5daddbd24e71c5088f0083a9e1e78d6f63d221cb Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sun, 9 Apr 2023 18:14:27 -0700
Subject: [PATCH v2 1/2] Fix heapdesc infomask array output.

---
 src/include/access/rmgrdesc_utils.h          | 38 +++++++++
 src/backend/access/rmgrdesc/heapdesc.c       | 84 ++++++++++++--------
 src/backend/access/rmgrdesc/rmgrdesc_utils.c | 20 -----
 3 files changed, 90 insertions(+), 52 deletions(-)

diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 00e614649..16916e3e8 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,6 +12,44 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
+/*
+ * Guidelines for rmgr descriptor routine authors:
+ *
+ * The goal of these guidelines is to avoid gratuitous inconsistencies across
+ * each rmgr, and to allow users to parse desc output strings without too much
+ * difficulty.  This is not an API specification or an interchange format.
+ * (Only heapam and nbtree desc routines follow these guidelines at present,
+ * in any case.)
+ *
+ * Record descriptions are similar to JSON style key/value objects.  However,
+ * there is no explicit "string" type/string escaping.  Top-level { } brackets
+ * should be omitted.  For example:
+ *
+ * snapshotConflictHorizon: 0, flags: 0x03
+ *
+ * Record descriptions may contain variable-length arrays.  For example:
+ *
+ * nunused: 5, unused: [1, 2, 3, 4, 5]
+ *
+ * Nested objects are supported via { } brackets.  They generally appear
+ * inside variable-length arrays.  For example:
+ *
+ * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+ *
+ * Try to output things in an order that faithfully represents the order of
+ * things in the physical WAL record struct.  It's a good idea if the number
+ * of items in the array appears before the array.
+ *
+ * It's okay for individual WAL record types to invent their own conventions.
+ * For example, heapam's PRUNE records output the follow representation of
+ * redirects:
+ *
+ * ... redirected: [39->46], ...
+ *
+ * Arguably the PRUNE desc routine should be using object notation instead.
+ * This ad-hoc representation of redirects has the advantage of being terse in
+ * a context where that might matter a lot.
+ */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 3bd083875..151569990 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -18,29 +18,53 @@
 #include "access/rmgrdesc_utils.h"
 
 static void
-out_infobits(StringInfo buf, uint8 infobits)
+infobits_desc(StringInfo buf, uint8 infobits, const char *keyname)
 {
-	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
-		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
-		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
-		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
-		(infobits & XLHL_KEYS_UPDATED) == 0)
-		return;
+	appendStringInfo(buf, "%s: [", keyname);
 
-	appendStringInfoString(buf, ", infobits: [");
+	Assert(buf->data[buf->len - 1] != ' ');
 
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, " IS_MULTI");
+		appendStringInfoString(buf, "IS_MULTI, ");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, ", LOCK_ONLY");
+		appendStringInfoString(buf, "LOCK_ONLY, ");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, ", EXCL_LOCK");
+		appendStringInfoString(buf, "EXCL_LOCK, ");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, ", KEYSHR_LOCK");
+		appendStringInfoString(buf, "KEYSHR_LOCK, ");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, ", KEYS_UPDATED");
+		appendStringInfoString(buf, "KEYS_UPDATED, ");
 
-	appendStringInfoString(buf, " ]");
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
+}
+
+static void
+truncate_flags_desc(StringInfo buf, uint8 flags)
+{
+	appendStringInfoString(buf, "flags: [");
+
+	if (flags & XLH_TRUNCATE_CASCADE)
+		appendStringInfoString(buf, "CASCADE, ");
+	if (flags & XLH_TRUNCATE_RESTART_SEQS)
+		appendStringInfoString(buf, "RESTART_SEQS, ");
+
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
 }
 
 static void
@@ -82,20 +106,20 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X, ",
 						 xlrec->offnum,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
 		appendStringInfo(buf, ", new off: %u, xmax %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
@@ -104,11 +128,11 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->old_offnum,
 						 xlrec->old_xmax,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
 		appendStringInfo(buf, ", new off: %u, xmax: %u",
 						 xlrec->new_offnum,
 						 xlrec->new_xmax);
@@ -117,13 +141,7 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
 
-		appendStringInfoString(buf, "flags: [");
-		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, " CASCADE");
-		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, ", RESTART_SEQS");
-		appendStringInfoString(buf, " ]");
-
+		truncate_flags_desc(buf, xlrec->flags);
 		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
 		appendStringInfoString(buf, ", relids:");
 		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids,
@@ -139,9 +157,9 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X, ",
 						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP_INPLACE)
 	{
@@ -230,7 +248,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 			OffsetNumber *offsets;
 
 			plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
-			offsets = (OffsetNumber *) &plans[xlrec->nplans];
+			offsets = (OffsetNumber *) ((char *) plans +
+										(xlrec->nplans *
+										 sizeof(xl_heap_freeze_plan)));
 			appendStringInfoString(buf, ", plans:");
 			array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
 					   &plan_elem_desc, &offsets);
@@ -260,9 +280,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X, ",
 						 xlrec->offnum, xlrec->xmax, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP2_NEW_CID)
 	{
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 3d16b1fcb..90051f0df 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,26 +16,6 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
-/*
- * Guidelines for formatting desc functions:
- *
- * member1_name: member1_value, member2_name: member2_value
- *
- * If the value is a list, please use:
- *
- * member3_name: [ member3_list_value1, member3_list_value2 ]
- *
- * The first item appended to the string should not be prepended by any spaces
- * or comma, however all subsequent appends to the string are responsible for
- * prepending themselves with a comma followed by a space.
- *
- * Flags should be in ALL CAPS.
- *
- * For lists/arrays of items, the number of those items should be listed at
- * the beginning with all of the other numbers.
- *
- * Composite objects in a list should be surrounded with { }.
- */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
-- 
2.40.0

From dff0f4691e7d8e2da607f7512148356afe8e4492 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sun, 9 Apr 2023 18:14:27 -0700
Subject: [PATCH v3 1/3] Fix heapdesc infomask array output.

---
 src/include/access/heapam_xlog.h             |   2 +-
 src/include/access/rmgrdesc_utils.h          |  39 +++++++
 src/backend/access/heap/heapam.c             |   6 +-
 src/backend/access/rmgrdesc/heapdesc.c       | 116 +++++++++++--------
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  20 ----
 5 files changed, 112 insertions(+), 71 deletions(-)

diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index e71d84895..bf1d05965 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -279,7 +279,7 @@ typedef struct xl_heap_vacuum
 /* This is what we need to know about lock */
 typedef struct xl_heap_lock
 {
-	TransactionId locking_xid;	/* might be a MultiXactId not xid */
+	TransactionId xmax;			/* might be a MultiXactId */
 	OffsetNumber offnum;		/* locked tuple's offset on page */
 	int8		infobits_set;	/* infomask and infomask2 bits to set */
 	uint8		flags;			/* XLH_LOCK_* flag bits */
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 00e614649..1686147f8 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,6 +12,45 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
+/*
+ * Guidelines for rmgr descriptor routine authors:
+ *
+ * The goal of these guidelines is to avoid gratuitous inconsistencies across
+ * each rmgr, and to allow users to parse desc output strings without too much
+ * difficulty.  This is not an API specification or an interchange format.
+ * (Only heapam and nbtree desc routines follow these guidelines at present,
+ * in any case.)
+ *
+ * Record descriptions are similar to JSON style key/value objects.  However,
+ * there is no explicit "string" type/string escaping.  Top-level { } brackets
+ * should be omitted.  For example:
+ *
+ * snapshotConflictHorizon: 0, flags: 0x03
+ *
+ * Record descriptions may contain variable-length arrays.  For example:
+ *
+ * nunused: 5, unused: [1, 2, 3, 4, 5]
+ *
+ * Nested objects are supported via { } brackets.  They generally appear
+ * inside variable-length arrays.  For example:
+ *
+ * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+ *
+ * Try to output things in an order that faithfully represents the order of
+ * things in the physical WAL record struct.  It's a good idea if the number
+ * of items in the array appears before the array.  It's also a good idea if
+ * key names are reliably unique (within the same nesting level).
+ *
+ * It's okay for individual WAL record types to invent their own conventions.
+ * For example, heapam's PRUNE records output the follow representation of
+ * redirects:
+ *
+ * ... redirected: [39->46], ...
+ *
+ * Arguably the PRUNE desc routine should be using object notation instead.
+ * This ad-hoc representation of redirects has the advantage of being terse in
+ * a context where that might matter a lot.
+ */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index f389ceee1..b300a4675 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -3567,7 +3567,7 @@ l2:
 			XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
 
 			xlrec.offnum = ItemPointerGetOffsetNumber(&oldtup.t_self);
-			xlrec.locking_xid = xmax_lock_old_tuple;
+			xlrec.xmax = xmax_lock_old_tuple;
 			xlrec.infobits_set = compute_infobits(oldtup.t_data->t_infomask,
 												  oldtup.t_data->t_infomask2);
 			xlrec.flags =
@@ -4777,7 +4777,7 @@ failed:
 		XLogRegisterBuffer(0, *buffer, REGBUF_STANDARD);
 
 		xlrec.offnum = ItemPointerGetOffsetNumber(&tuple->t_self);
-		xlrec.locking_xid = xid;
+		xlrec.xmax = xid;
 		xlrec.infobits_set = compute_infobits(new_infomask,
 											  tuple->t_data->t_infomask2);
 		xlrec.flags = cleared_all_frozen ? XLH_LOCK_ALL_FROZEN_CLEARED : 0;
@@ -9848,7 +9848,7 @@ heap_xlog_lock(XLogReaderState *record)
 						   BufferGetBlockNumber(buffer),
 						   offnum);
 		}
-		HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
+		HeapTupleHeaderSetXmax(htup, xlrec->xmax);
 		HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
 		PageSetLSN(page, lsn);
 		MarkBufferDirty(buffer);
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 3bd083875..de91a43f9 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -17,30 +17,58 @@
 #include "access/heapam_xlog.h"
 #include "access/rmgrdesc_utils.h"
 
+/*
+ * NOTE: "keyname" argument cannot have trailing spaces or punctuation
+ * characters
+ */
 static void
-out_infobits(StringInfo buf, uint8 infobits)
+infobits_desc(StringInfo buf, uint8 infobits, const char *keyname)
 {
-	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
-		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
-		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
-		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
-		(infobits & XLHL_KEYS_UPDATED) == 0)
-		return;
+	appendStringInfo(buf, "%s: [", keyname);
 
-	appendStringInfoString(buf, ", infobits: [");
+	Assert(buf->data[buf->len - 1] != ' ');
 
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, " IS_MULTI");
+		appendStringInfoString(buf, "IS_MULTI, ");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, ", LOCK_ONLY");
+		appendStringInfoString(buf, "LOCK_ONLY, ");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, ", EXCL_LOCK");
+		appendStringInfoString(buf, "EXCL_LOCK, ");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, ", KEYSHR_LOCK");
+		appendStringInfoString(buf, "KEYSHR_LOCK, ");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, ", KEYS_UPDATED");
+		appendStringInfoString(buf, "KEYS_UPDATED, ");
 
-	appendStringInfoString(buf, " ]");
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
+}
+
+static void
+truncate_flags_desc(StringInfo buf, uint8 flags)
+{
+	appendStringInfoString(buf, "flags: [");
+
+	if (flags & XLH_TRUNCATE_CASCADE)
+		appendStringInfoString(buf, "CASCADE, ");
+	if (flags & XLH_TRUNCATE_RESTART_SEQS)
+		appendStringInfoString(buf, "RESTART_SEQS, ");
+
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
 }
 
 static void
@@ -82,48 +110,36 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off: %u, flags: 0x%02X",
+		appendStringInfo(buf, "off: %u, flags: 0x%02X, ",
 						 xlrec->offnum,
 						 xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
 	}
 	else if (info == XLOG_HEAP_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->old_offnum,
-						 xlrec->old_xmax,
-						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, ", new off: %u, xmax %u",
-						 xlrec->new_offnum,
-						 xlrec->new_xmax);
+		appendStringInfo(buf, "old_off: %u, old_xmax: %u, ",
+						 xlrec->old_offnum, xlrec->old_xmax);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
+		appendStringInfo(buf, ", flags: 0x%02X, new_off: %u, new_xmax: %u",
+						 xlrec->flags, xlrec->new_offnum, xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_HOT_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->old_offnum,
-						 xlrec->old_xmax,
-						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, ", new off: %u, xmax: %u",
-						 xlrec->new_offnum,
-						 xlrec->new_xmax);
+		appendStringInfo(buf, "old_off: %u, old_xmax: %u, ",
+						 xlrec->old_offnum, xlrec->old_xmax);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
+		appendStringInfo(buf, ", flags: 0x%02X, new_off: %u, new_xmax: %u",
+						 xlrec->flags, xlrec->new_offnum, xlrec->new_xmax);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
 
-		appendStringInfoString(buf, "flags: [");
-		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, " CASCADE");
-		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, ", RESTART_SEQS");
-		appendStringInfoString(buf, " ]");
-
+		truncate_flags_desc(buf, xlrec->flags);
 		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
 		appendStringInfoString(buf, ", relids:");
 		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids,
@@ -139,9 +155,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
-						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		appendStringInfo(buf, "xmax: %u, off: %u, ",
+						 xlrec->xmax, xlrec->offnum);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
+		appendStringInfo(buf, ", flags: 0x%02X", xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_INPLACE)
 	{
@@ -230,7 +247,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 			OffsetNumber *offsets;
 
 			plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
-			offsets = (OffsetNumber *) &plans[xlrec->nplans];
+			offsets = (OffsetNumber *) ((char *) plans +
+										(xlrec->nplans *
+										 sizeof(xl_heap_freeze_plan)));
 			appendStringInfoString(buf, ", plans:");
 			array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
 					   &plan_elem_desc, &offsets);
@@ -251,18 +270,21 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
 
-		appendStringInfoString(buf, ", offsets:");
 		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+		{
+			appendStringInfoString(buf, ", offsets:");
 			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber),
 					   xlrec->ntuples, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->offnum, xlrec->xmax, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		appendStringInfo(buf, "xmax: %u, off: %u, ",
+						 xlrec->xmax, xlrec->offnum);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
+		appendStringInfo(buf, ", flags: 0x%02X", xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_NEW_CID)
 	{
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 3d16b1fcb..90051f0df 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,26 +16,6 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
-/*
- * Guidelines for formatting desc functions:
- *
- * member1_name: member1_value, member2_name: member2_value
- *
- * If the value is a list, please use:
- *
- * member3_name: [ member3_list_value1, member3_list_value2 ]
- *
- * The first item appended to the string should not be prepended by any spaces
- * or comma, however all subsequent appends to the string are responsible for
- * prepending themselves with a comma followed by a space.
- *
- * Flags should be in ALL CAPS.
- *
- * For lists/arrays of items, the number of those items should be listed at
- * the beginning with all of the other numbers.
- *
- * Composite objects in a list should be surrounded with { }.
- */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
-- 
2.40.0

From a53bc02b3bffd910b28ce03b4a36053b6683c436 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sun, 9 Apr 2023 18:14:27 -0700
Subject: [PATCH v4 1/3] Fix heapdesc infomask array output.

---
 src/include/access/heapam_xlog.h             |   2 +-
 src/include/access/rmgrdesc_utils.h          |  39 ++++++
 src/backend/access/heap/heapam.c             |   6 +-
 src/backend/access/rmgrdesc/heapdesc.c       | 120 +++++++++++--------
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  20 ----
 5 files changed, 114 insertions(+), 73 deletions(-)

diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index e71d84895..bf1d05965 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -279,7 +279,7 @@ typedef struct xl_heap_vacuum
 /* This is what we need to know about lock */
 typedef struct xl_heap_lock
 {
-	TransactionId locking_xid;	/* might be a MultiXactId not xid */
+	TransactionId xmax;			/* might be a MultiXactId */
 	OffsetNumber offnum;		/* locked tuple's offset on page */
 	int8		infobits_set;	/* infomask and infomask2 bits to set */
 	uint8		flags;			/* XLH_LOCK_* flag bits */
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index 00e614649..1686147f8 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,6 +12,45 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
+/*
+ * Guidelines for rmgr descriptor routine authors:
+ *
+ * The goal of these guidelines is to avoid gratuitous inconsistencies across
+ * each rmgr, and to allow users to parse desc output strings without too much
+ * difficulty.  This is not an API specification or an interchange format.
+ * (Only heapam and nbtree desc routines follow these guidelines at present,
+ * in any case.)
+ *
+ * Record descriptions are similar to JSON style key/value objects.  However,
+ * there is no explicit "string" type/string escaping.  Top-level { } brackets
+ * should be omitted.  For example:
+ *
+ * snapshotConflictHorizon: 0, flags: 0x03
+ *
+ * Record descriptions may contain variable-length arrays.  For example:
+ *
+ * nunused: 5, unused: [1, 2, 3, 4, 5]
+ *
+ * Nested objects are supported via { } brackets.  They generally appear
+ * inside variable-length arrays.  For example:
+ *
+ * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+ *
+ * Try to output things in an order that faithfully represents the order of
+ * things in the physical WAL record struct.  It's a good idea if the number
+ * of items in the array appears before the array.  It's also a good idea if
+ * key names are reliably unique (within the same nesting level).
+ *
+ * It's okay for individual WAL record types to invent their own conventions.
+ * For example, heapam's PRUNE records output the follow representation of
+ * redirects:
+ *
+ * ... redirected: [39->46], ...
+ *
+ * Arguably the PRUNE desc routine should be using object notation instead.
+ * This ad-hoc representation of redirects has the advantage of being terse in
+ * a context where that might matter a lot.
+ */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index f389ceee1..b300a4675 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -3567,7 +3567,7 @@ l2:
 			XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
 
 			xlrec.offnum = ItemPointerGetOffsetNumber(&oldtup.t_self);
-			xlrec.locking_xid = xmax_lock_old_tuple;
+			xlrec.xmax = xmax_lock_old_tuple;
 			xlrec.infobits_set = compute_infobits(oldtup.t_data->t_infomask,
 												  oldtup.t_data->t_infomask2);
 			xlrec.flags =
@@ -4777,7 +4777,7 @@ failed:
 		XLogRegisterBuffer(0, *buffer, REGBUF_STANDARD);
 
 		xlrec.offnum = ItemPointerGetOffsetNumber(&tuple->t_self);
-		xlrec.locking_xid = xid;
+		xlrec.xmax = xid;
 		xlrec.infobits_set = compute_infobits(new_infomask,
 											  tuple->t_data->t_infomask2);
 		xlrec.flags = cleared_all_frozen ? XLH_LOCK_ALL_FROZEN_CLEARED : 0;
@@ -9848,7 +9848,7 @@ heap_xlog_lock(XLogReaderState *record)
 						   BufferGetBlockNumber(buffer),
 						   offnum);
 		}
-		HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
+		HeapTupleHeaderSetXmax(htup, xlrec->xmax);
 		HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
 		PageSetLSN(page, lsn);
 		MarkBufferDirty(buffer);
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 3bd083875..d182d8048 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -17,30 +17,58 @@
 #include "access/heapam_xlog.h"
 #include "access/rmgrdesc_utils.h"
 
+/*
+ * NOTE: "keyname" argument cannot have trailing spaces or punctuation
+ * characters
+ */
 static void
-out_infobits(StringInfo buf, uint8 infobits)
+infobits_desc(StringInfo buf, uint8 infobits, const char *keyname)
 {
-	if ((infobits & XLHL_XMAX_IS_MULTI) == 0 &&
-		(infobits & XLHL_XMAX_LOCK_ONLY) == 0 &&
-		(infobits & XLHL_XMAX_EXCL_LOCK) == 0 &&
-		(infobits & XLHL_XMAX_KEYSHR_LOCK) == 0 &&
-		(infobits & XLHL_KEYS_UPDATED) == 0)
-		return;
+	appendStringInfo(buf, "%s: [", keyname);
 
-	appendStringInfoString(buf, ", infobits: [");
+	Assert(buf->data[buf->len - 1] != ' ');
 
 	if (infobits & XLHL_XMAX_IS_MULTI)
-		appendStringInfoString(buf, " IS_MULTI");
+		appendStringInfoString(buf, "IS_MULTI, ");
 	if (infobits & XLHL_XMAX_LOCK_ONLY)
-		appendStringInfoString(buf, ", LOCK_ONLY");
+		appendStringInfoString(buf, "LOCK_ONLY, ");
 	if (infobits & XLHL_XMAX_EXCL_LOCK)
-		appendStringInfoString(buf, ", EXCL_LOCK");
+		appendStringInfoString(buf, "EXCL_LOCK, ");
 	if (infobits & XLHL_XMAX_KEYSHR_LOCK)
-		appendStringInfoString(buf, ", KEYSHR_LOCK");
+		appendStringInfoString(buf, "KEYSHR_LOCK, ");
 	if (infobits & XLHL_KEYS_UPDATED)
-		appendStringInfoString(buf, ", KEYS_UPDATED");
+		appendStringInfoString(buf, "KEYS_UPDATED, ");
 
-	appendStringInfoString(buf, " ]");
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
+}
+
+static void
+truncate_flags_desc(StringInfo buf, uint8 flags)
+{
+	appendStringInfoString(buf, "flags: [");
+
+	if (flags & XLH_TRUNCATE_CASCADE)
+		appendStringInfoString(buf, "CASCADE, ");
+	if (flags & XLH_TRUNCATE_RESTART_SEQS)
+		appendStringInfoString(buf, "RESTART_SEQS, ");
+
+	if (buf->data[buf->len - 1] == ' ')
+	{
+		/* Truncate-away final unneeded ", "  */
+		Assert(buf->data[buf->len - 2] == ',');
+		buf->len -= 2;
+		buf->data[buf->len] = '\0';
+	}
+
+	appendStringInfoString(buf, "]");
 }
 
 static void
@@ -82,48 +110,36 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_delete *xlrec = (xl_heap_delete *) rec;
 
-		appendStringInfo(buf, "off: %u, flags: 0x%02X",
-						 xlrec->offnum,
-						 xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		appendStringInfo(buf, "xmax: %u, off: %u, ",
+						 xlrec->xmax, xlrec->offnum);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
+		appendStringInfo(buf, ", flags: 0x%02X", xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->old_offnum,
-						 xlrec->old_xmax,
-						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, ", new off: %u, xmax %u",
-						 xlrec->new_offnum,
-						 xlrec->new_xmax);
+		appendStringInfo(buf, "old_xmax: %u, old_off: %u, ",
+						 xlrec->old_xmax, xlrec->old_offnum);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
+		appendStringInfo(buf, ", flags: 0x%02X, new_xmax: %u, new_off: %u",
+						 xlrec->flags, xlrec->new_xmax, xlrec->new_offnum);
 	}
 	else if (info == XLOG_HEAP_HOT_UPDATE)
 	{
 		xl_heap_update *xlrec = (xl_heap_update *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->old_offnum,
-						 xlrec->old_xmax,
-						 xlrec->flags);
-		out_infobits(buf, xlrec->old_infobits_set);
-		appendStringInfo(buf, ", new off: %u, xmax: %u",
-						 xlrec->new_offnum,
-						 xlrec->new_xmax);
+		appendStringInfo(buf, "old_xmax: %u, old_off: %u, ",
+						 xlrec->old_xmax, xlrec->old_offnum);
+		infobits_desc(buf, xlrec->old_infobits_set, "old_infobits");
+		appendStringInfo(buf, ", flags: 0x%02X, new_xmax: %u, new_off: %u",
+						 xlrec->flags, xlrec->new_xmax, xlrec->new_offnum);
 	}
 	else if (info == XLOG_HEAP_TRUNCATE)
 	{
 		xl_heap_truncate *xlrec = (xl_heap_truncate *) rec;
 
-		appendStringInfoString(buf, "flags: [");
-		if (xlrec->flags & XLH_TRUNCATE_CASCADE)
-			appendStringInfoString(buf, " CASCADE");
-		if (xlrec->flags & XLH_TRUNCATE_RESTART_SEQS)
-			appendStringInfoString(buf, ", RESTART_SEQS");
-		appendStringInfoString(buf, " ]");
-
+		truncate_flags_desc(buf, xlrec->flags);
 		appendStringInfo(buf, ", nrelids: %u", xlrec->nrelids);
 		appendStringInfoString(buf, ", relids:");
 		array_desc(buf, xlrec->relids, sizeof(Oid), xlrec->nrelids,
@@ -139,9 +155,10 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_heap_lock *xlrec = (xl_heap_lock *) rec;
 
-		appendStringInfo(buf, "off: %u, xid: %u, flags: 0x%02X",
-						 xlrec->offnum, xlrec->locking_xid, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		appendStringInfo(buf, "xmax: %u, off: %u, ",
+						 xlrec->xmax, xlrec->offnum);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
+		appendStringInfo(buf, ", flags: 0x%02X", xlrec->flags);
 	}
 	else if (info == XLOG_HEAP_INPLACE)
 	{
@@ -230,7 +247,9 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 			OffsetNumber *offsets;
 
 			plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
-			offsets = (OffsetNumber *) &plans[xlrec->nplans];
+			offsets = (OffsetNumber *) ((char *) plans +
+										(xlrec->nplans *
+										 sizeof(xl_heap_freeze_plan)));
 			appendStringInfoString(buf, ", plans:");
 			array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
 					   &plan_elem_desc, &offsets);
@@ -251,18 +270,21 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
 		appendStringInfo(buf, "ntuples: %d, flags: 0x%02X", xlrec->ntuples,
 						 xlrec->flags);
 
-		appendStringInfoString(buf, ", offsets:");
 		if (!XLogRecHasBlockImage(record, 0) && !isinit)
+		{
+			appendStringInfoString(buf, ", offsets:");
 			array_desc(buf, xlrec->offsets, sizeof(OffsetNumber),
 					   xlrec->ntuples, &offset_elem_desc, NULL);
+		}
 	}
 	else if (info == XLOG_HEAP2_LOCK_UPDATED)
 	{
 		xl_heap_lock_updated *xlrec = (xl_heap_lock_updated *) rec;
 
-		appendStringInfo(buf, "off: %u, xmax: %u, flags: 0x%02X",
-						 xlrec->offnum, xlrec->xmax, xlrec->flags);
-		out_infobits(buf, xlrec->infobits_set);
+		appendStringInfo(buf, "xmax: %u, off: %u, ",
+						 xlrec->xmax, xlrec->offnum);
+		infobits_desc(buf, xlrec->infobits_set, "infobits");
+		appendStringInfo(buf, ", flags: 0x%02X", xlrec->flags);
 	}
 	else if (info == XLOG_HEAP2_NEW_CID)
 	{
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 3d16b1fcb..90051f0df 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,26 +16,6 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
-/*
- * Guidelines for formatting desc functions:
- *
- * member1_name: member1_value, member2_name: member2_value
- *
- * If the value is a list, please use:
- *
- * member3_name: [ member3_list_value1, member3_list_value2 ]
- *
- * The first item appended to the string should not be prepended by any spaces
- * or comma, however all subsequent appends to the string are responsible for
- * prepending themselves with a comma followed by a space.
- *
- * Flags should be in ALL CAPS.
- *
- * For lists/arrays of items, the number of those items should be listed at
- * the beginning with all of the other numbers.
- *
- * Composite objects in a list should be surrounded with { }.
- */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
-- 
2.40.0

From 5261e3b4c373aef47458bed14d339d4ea2e6df5a Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Mon, 10 Jul 2023 10:41:35 +0300
Subject: [PATCH v1 1/1] Add rmgrdesc README.

In the README, briefly explain what rmgrdesc functions are, and why they
are in a separate directory. Commit c03c2eae0a added some guidelines on
the preferred output format; move that to the README too.

Discussion: TODO
---
 src/backend/access/rmgrdesc/README           | 60 ++++++++++++++++++++
 src/backend/access/rmgrdesc/rmgrdesc_utils.c |  4 ++
 src/include/access/rmgrdesc_utils.h          | 44 --------------
 3 files changed, 64 insertions(+), 44 deletions(-)
 create mode 100644 src/backend/access/rmgrdesc/README

diff --git a/src/backend/access/rmgrdesc/README b/src/backend/access/rmgrdesc/README
new file mode 100644
index 0000000000..abe84b9f11
--- /dev/null
+++ b/src/backend/access/rmgrdesc/README
@@ -0,0 +1,60 @@
+src/backend/access/rmgrdesc/README
+
+WAL resource manager description functions
+==========================================
+
+For debugging purposes, there is a "description function", or rmgrdesc
+function, for each WAL resource manager. The rmgrdesc function parses the WAL
+record and prints the contents of the WAL record in a somewhat human-readable
+format.
+
+The rmgrdesc functions for all resource managers are gathered in this
+directory, because they are also used in the stand-alone pg_waldump program.
+They could potentially be used by out-of-tree debugging tools too, although
+the the functions or the output format should not be considered a stable API.
+
+Guidelines for rmgrdesc output format
+=====================================
+
+The goal of these guidelines is to avoid gratuitous inconsistencies across
+each rmgr, and to allow users to parse desc output strings without too much
+difficulty.  This is not an API specification or an interchange format.
+(Only heapam and nbtree desc routines follow these guidelines at present, in
+any case.)
+
+Record descriptions are similar to JSON style key/value objects.  However,
+there is no explicit "string" type/string escaping.  Top-level { } brackets
+should be omitted.  For example:
+
+snapshotConflictHorizon: 0, flags: 0x03
+
+Record descriptions may contain variable-length arrays.  For example:
+
+nunused: 5, unused: [1, 2, 3, 4, 5]
+
+Nested objects are supported via { } brackets.  They generally appear inside
+variable-length arrays.  For example:
+
+ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
+
+Try to output things in an order that faithfully represents the order of
+fields from the underlying physical WAL record struct.  Key names should be
+unique (at the same nesting level) to make parsing easy.  It's a good idea if
+the number of items in the array appears before the array.
+
+It's okay for individual WAL record types to invent their own conventions.
+For example, Heap2's PRUNE record descriptions use a custom array format for
+the record's "redirected" field:
+
+... redirected: [1->4, 5->9], dead: [10, 11], unused: [3, 7, 8]
+
+Arguably the desc routine should be using object notation for this instead.
+However, there is value in using a custom format when it conveys useful
+information about the underlying physical data structures.
+
+This ad-hoc format has the advantage of being close to the format used for
+the "dead" and "unused" arrays (which follow the standard desc convention for
+page offset number arrays).  It suggests that the "redirected" elements shown
+are just pairs of page offset numbers (which is how it really works).
+
+rmgrdesc_utils.c contains some helper functions to print data in this format.
diff --git a/src/backend/access/rmgrdesc/rmgrdesc_utils.c b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
index 90051f0df9..808770524d 100644
--- a/src/backend/access/rmgrdesc/rmgrdesc_utils.c
+++ b/src/backend/access/rmgrdesc/rmgrdesc_utils.c
@@ -16,6 +16,10 @@
 #include "access/rmgrdesc_utils.h"
 #include "storage/off.h"
 
+/*
+ * Helper function to print an array, in the format described in the
+ * README.
+ */
 void
 array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 		   void (*elem_desc) (StringInfo buf, void *elem, void *data),
diff --git a/src/include/access/rmgrdesc_utils.h b/src/include/access/rmgrdesc_utils.h
index bd414699f2..c754d55621 100644
--- a/src/include/access/rmgrdesc_utils.h
+++ b/src/include/access/rmgrdesc_utils.h
@@ -12,50 +12,6 @@
 #ifndef RMGRDESC_UTILS_H_
 #define RMGRDESC_UTILS_H_
 
-/*
- * Guidelines for rmgrdesc routine authors:
- *
- * The goal of these guidelines is to avoid gratuitous inconsistencies across
- * each rmgr, and to allow users to parse desc output strings without too much
- * difficulty.  This is not an API specification or an interchange format.
- * (Only heapam and nbtree desc routines follow these guidelines at present,
- * in any case.)
- *
- * Record descriptions are similar to JSON style key/value objects.  However,
- * there is no explicit "string" type/string escaping.  Top-level { } brackets
- * should be omitted.  For example:
- *
- * snapshotConflictHorizon: 0, flags: 0x03
- *
- * Record descriptions may contain variable-length arrays.  For example:
- *
- * nunused: 5, unused: [1, 2, 3, 4, 5]
- *
- * Nested objects are supported via { } brackets.  They generally appear
- * inside variable-length arrays.  For example:
- *
- * ndeleted: 0, nupdated: 1, deleted: [], updated: [{ off: 45, nptids: 1, ptids: [0] }]
- *
- * Try to output things in an order that faithfully represents the order of
- * fields from the underlying physical WAL record struct.  Key names should be
- * unique (at the same nesting level) to make parsing easy.  It's a good idea
- * if the number of items in the array appears before the array.
- *
- * It's okay for individual WAL record types to invent their own conventions.
- * For example, Heap2's PRUNE record descriptions use a custom array format
- * for the record's "redirected" field:
- *
- * ... redirected: [1->4, 5->9], dead: [10, 11], unused: [3, 7, 8]
- *
- * Arguably the desc routine should be using object notation for this instead.
- * However, there is value in using a custom format when it conveys useful
- * information about the underlying physical data structures.
- *
- * This ad-hoc format has the advantage of being close to the format used for
- * the "dead" and "unused" arrays (which follow the standard desc convention
- * for page offset number arrays).  It suggests that the "redirected" elements
- * shown are just pairs of page offset numbers (which is how it really works).
- */
 extern void array_desc(StringInfo buf, void *array, size_t elem_size, int count,
 					   void (*elem_desc) (StringInfo buf, void *elem, void *data),
 					   void *data);
-- 
2.30.2

From b358cdb295468c59ba0ac1320f46ccf3f1591b29 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Tue, 21 Mar 2023 14:40:43 -0700
Subject: [PATCH v2] Record which PRUNE records are from VACUUM.

---
 src/include/access/heapam.h            |  2 +-
 src/include/access/heapam_xlog.h       |  8 +++++++-
 src/backend/access/heap/pruneheap.c    | 25 +++++++++++++++----------
 src/backend/access/rmgrdesc/heapdesc.c |  3 +++
 4 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index a2d7a0ea7..174073eb2 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -321,7 +321,7 @@ extern void heap_page_prune_opt(Relation relation, Buffer buffer);
 extern void heap_page_prune(Relation relation, Buffer buffer,
 							struct GlobalVisState *vistest,
 							PruneResult *presult,
-							OffsetNumber *off_loc);
+							OffsetNumber *off_loc_vacuum);
 extern void heap_page_prune_execute(Buffer buffer,
 									OffsetNumber *redirected, int nredirected,
 									OffsetNumber *nowdead, int ndead,
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index a03845078..d4c000f97 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -48,7 +48,7 @@
  * We ran out of opcodes, so heapam.c now has a second RmgrId.  These opcodes
  * are associated with RM_HEAP2_ID, but are not logically different from
  * the ones above associated with RM_HEAP_ID.  XLOG_HEAP_OPMASK applies to
- * these, too.
+ * these, too.  The BYVACUUM bit is used in place of RM_HEAP_ID's init bit.
  */
 #define XLOG_HEAP2_REWRITE		0x00
 #define XLOG_HEAP2_PRUNE		0x10
@@ -59,6 +59,12 @@
 #define XLOG_HEAP2_LOCK_UPDATED 0x60
 #define XLOG_HEAP2_NEW_CID		0x70
 
+/*
+ * RM_HEAP2_ID operations that take place during VACUUM set the BYVACUUM bit
+ * as instrumentation.  Only set in XLOG_HEAP2_PRUNE records, for now.
+ */
+#define XLOG_HEAP2_BYVACUUM		0x80
+
 /*
  * xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
  */
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index c5f1abd95..37cc31e0f 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -193,8 +193,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  * (see heap_prune_satisfies_vacuum and
  * HeapTupleSatisfiesVacuum).
  *
- * off_loc is the offset location required by the caller to use in error
- * callback.
+ * off_loc_vacuum is the offset location required by VACUUM caller to use in
+ * error callback.  Opportunistic pruning caller should pass NULL.
  *
  * presult contains output parameters needed by callers such as the number of
  * tuples removed and the number of line pointers newly marked LP_DEAD.
@@ -204,7 +204,7 @@ void
 heap_page_prune(Relation relation, Buffer buffer,
 				GlobalVisState *vistest,
 				PruneResult *presult,
-				OffsetNumber *off_loc)
+				OffsetNumber *off_loc_vacuum)
 {
 	Page		page = BufferGetPage(buffer);
 	BlockNumber blockno = BufferGetBlockNumber(buffer);
@@ -284,8 +284,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 		 * Set the offset number so that we can display it along with any
 		 * error that occurred while processing this tuple.
 		 */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		presult->htsv[offnum] = heap_prune_satisfies_vacuum(&prstate, &tup,
 															buffer);
@@ -303,8 +303,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 			continue;
 
 		/* see preceding loop */
-		if (off_loc)
-			*off_loc = offnum;
+		if (off_loc_vacuum)
+			*off_loc_vacuum = offnum;
 
 		/* Nothing to do if slot is empty or already dead */
 		itemid = PageGetItemId(page, offnum);
@@ -317,8 +317,8 @@ heap_page_prune(Relation relation, Buffer buffer,
 	}
 
 	/* Clear the offset information once we have processed the given page. */
-	if (off_loc)
-		*off_loc = InvalidOffsetNumber;
+	if (off_loc_vacuum)
+		*off_loc_vacuum = InvalidOffsetNumber;
 
 	/* Any error while applying the changes is critical */
 	START_CRIT_SECTION();
@@ -356,6 +356,7 @@ heap_page_prune(Relation relation, Buffer buffer,
 		if (RelationNeedsWAL(relation))
 		{
 			xl_heap_prune xlrec;
+			uint8		info = XLOG_HEAP2_PRUNE;
 			XLogRecPtr	recptr;
 
 			xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
@@ -386,7 +387,11 @@ heap_page_prune(Relation relation, Buffer buffer,
 				XLogRegisterBufData(0, (char *) prstate.nowunused,
 									prstate.nunused * sizeof(OffsetNumber));
 
-			recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+			/* Set bit indicating pruning by VACUUM where appropriate */
+			if (off_loc_vacuum)
+				info |= XLOG_HEAP2_BYVACUUM;
+
+			recptr = XLogInsert(RM_HEAP2_ID, info);
 
 			PageSetLSN(BufferGetPage(buffer), recptr);
 		}
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index f382c0f62..c456d6986 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -356,6 +356,9 @@ heap2_identify(uint8 info)
 		case XLOG_HEAP2_PRUNE:
 			id = "PRUNE";
 			break;
+		case XLOG_HEAP2_PRUNE | XLOG_HEAP2_BYVACUUM:
+			id = "PRUNE+BYVACUUM";
+			break;
 		case XLOG_HEAP2_VACUUM:
 			id = "VACUUM";
 			break;
-- 
2.43.0