[PATCH] Add extra statistics to explain for Nested Loop

From: "Ekaterina Sokolova" <e.sokolova@postgrespro.ru>
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 41317f18374..2132d82fe79 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1568,29 +1568,64 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		min_r = planstate->instrument->min_tuples;
+		double		max_r = planstate->instrument->max_tuples;
+		double		min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
+			if (nodeTag(plan) == T_NestLoop) {
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f min_time=%.3f max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 min_r, rows, max_r, nloops);
+			}
 			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
+			{
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, rows, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual rows=%.0f loops=%.0f)",
+									 rows, nloops);
+			}
 		}
 		else
 		{
-			if (es->timing)
+			if (nodeTag(plan) == T_NestLoop) {
+				if (es->timing) {
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+					ExplainPropertyFloat("Min Time", "s", min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Max Time", "s", max_t_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+			}
+			else
 			{
-				ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
-									 3, es);
+				if (es->timing) {
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
 	else if (es->analyze)
@@ -1599,6 +1634,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1624,39 +1660,78 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		nloops = instrument->nloops;
 			double		startup_ms;
 			double		total_ms;
+			double		min_t_ms;
+			double		max_t_ms;
 			double		rows;
+			double		min_r;
+			double		max_r;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
+			min_t_ms = 1000.0 * planstate->instrument->min_t;
+			max_t_ms = 1000.0 * planstate->instrument->max_t;
 			rows = instrument->ntuples / nloops;
+			min_r = planstate->instrument->min_tuples;
+			max_r = planstate->instrument->max_tuples;
 
 			ExplainOpenWorker(n, es);
 
 			if (es->format == EXPLAIN_FORMAT_TEXT)
 			{
 				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
+				if (nodeTag(plan) == T_NestLoop) {
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f min_time=%.3f  max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 min_r, rows, max_r, nloops);
+				}
 				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
+				{
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, rows, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual rows=%.0f loops=%.0f\n",
+										 rows, nloops);
+				}
 			}
 			else
 			{
-				if (es->timing)
+				if (nodeTag(plan) == T_NestLoop) {
+					if (es->timing) {
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+						ExplainPropertyFloat("Min Time", "ms",
+											 min_t_ms, 3, es);
+						ExplainPropertyFloat("Max Time", "ms",
+											 max_t_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+				}
+				else
 				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
+					if (es->timing) {
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
 			ExplainCloseWorker(n, es);
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index fbedb5aaf60..effe8516dba 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -118,9 +118,8 @@ InstrStopNode(Instrumentation *instr, double nTuples)
 
 /* Finish a run cycle for a plan node */
 void
-InstrEndLoop(Instrumentation *instr)
-{
-	double		totaltime;
+InstrEndLoop(Instrumentation *instr) {
+	double totaltime;
 
 	/* Skip if nothing has happened, or already shut down */
 	if (!instr->running)
@@ -134,7 +133,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+	if (instr->nloops == 0)					/* this is first loop */
+	{
+		if (instr->min_t == 0)
+		{
+			instr->min_t = totaltime;		/* init min_t */
+		}
+		if (instr->min_tuples == 0)
+		{
+			instr->min_tuples = instr->tuplecount;	/* init min_tuples */
+		}
+	}
+	if (instr->min_t > totaltime)
+	{
+		instr->min_t = totaltime;
+	}
+	if (instr->max_t < totaltime)
+	{
+		instr->max_t = totaltime;
+	}
 	instr->ntuples += instr->tuplecount;
+	if (instr->min_tuples > instr->tuplecount)
+	{
+		instr->min_tuples = instr->tuplecount;
+	}
+	if (instr->max_tuples < instr->tuplecount)
+	{
+		instr->max_tuples = instr->tuplecount;
+	}
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 9dc3ecb07d7..996433e9bb1 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,7 +66,11 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all loops */
+	double		max_tuples;		/* max counter of produced tuples for all loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 50d2a7e4b97..ba864a57677 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1929,6 +1929,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
@@ -2065,7 +2067,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{0,0,1}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2099,7 +2101,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{0,0,1}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2132,7 +2134,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,3}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2164,7 +2166,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: N
@@ -2198,7 +2200,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: N
@@ -2441,7 +2443,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
    Update on ab_a1_b1 ab_a1_1
    Update on ab_a1_b2 ab_a1_2
    Update on ab_a1_b3 ab_a1_3
-   ->  Nested Loop (actual rows=0 loops=1)
+   ->  Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2461,7 +2463,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
                      Recheck Cond: (a = 1)
                      ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0 loops=1)
                            Index Cond: (a = 1)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2482,7 +2484,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
                      Heap Blocks: exact=1
                      ->  Bitmap Index Scan on ab_a1_b2_a_idx (actual rows=1 loops=1)
                            Index Cond: (a = 1)
-   ->  Nested Loop (actual rows=0 loops=1)
+   ->  Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2523,7 +2525,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
    Update on ab_a1_b3 ab_a1_3
    InitPlan 1 (returns $0)
      ->  Result (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b1 ab_a1_1 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2533,7 +2535,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
                            Filter: (b = $0)
                      ->  Seq Scan on ab_a2_b3 ab_a2_3 (never executed)
                            Filter: (b = $0)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b2 ab_a1_2 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2543,7 +2545,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
                            Filter: (b = $0)
                      ->  Seq Scan on ab_a2_b3 ab_a2_3 (never executed)
                            Filter: (b = $0)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b3 ab_a1_3 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2589,7 +2591,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 > tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=6 loops=1)
+ Nested Loop (actual min_rows=6 rows=6 max_rows=6 loops=1)
    ->  Seq Scan on tbl1 (actual rows=2 loops=1)
    ->  Append (actual rows=3 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2 loops=2)
@@ -2610,7 +2612,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=2 loops=1)
+ Nested Loop (actual min_rows=2 rows=2 max_rows=2 loops=1)
    ->  Seq Scan on tbl1 (actual rows=2 loops=1)
    ->  Append (actual rows=1 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2655,7 +2657,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=23 loops=1)
+ Nested Loop (actual min_rows=23 rows=23 max_rows=23 loops=1)
    ->  Seq Scan on tbl1 (actual rows=5 loops=1)
    ->  Append (actual rows=5 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2 loops=5)
@@ -2676,7 +2678,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=3 loops=1)
+ Nested Loop (actual min_rows=3 rows=3 max_rows=3 loops=1)
    ->  Seq Scan on tbl1 (actual rows=5 loops=1)
    ->  Append (actual rows=1 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2740,7 +2742,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 < tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=1 loops=1)
+ Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
    ->  Seq Scan on tbl1 (actual rows=1 loops=1)
    ->  Append (actual rows=1 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2772,7 +2774,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
                             QUERY PLAN                             
 -------------------------------------------------------------------
- Nested Loop (actual rows=0 loops=1)
+ Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
    ->  Seq Scan on tbl1 (actual rows=1 loops=1)
    ->  Append (actual rows=0 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 9b0c418db71..e8ccd903b41 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -547,10 +547,10 @@ alter table tenk2 set (parallel_workers = 0);
 explain (analyze, timing off, summary off, costs off)
    select count(*) from tenk1, tenk2 where tenk1.hundred > 1
         and tenk2.thousand=0;
-                                QUERY PLAN                                
---------------------------------------------------------------------------
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
  Aggregate (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=98000 loops=1)
+   ->  Nested Loop (actual min_rows=98000 rows=98000 max_rows=98000 loops=1)
          ->  Seq Scan on tenk2 (actual rows=10 loops=1)
                Filter: (thousand = 0)
                Rows Removed by Filter: 9990
@@ -581,9 +581,9 @@ begin
 end;
 $$;
 select * from explain_parallel_sort_stats();
-                       explain_parallel_sort_stats                        
---------------------------------------------------------------------------
- Nested Loop Left Join (actual rows=30000 loops=1)
+                           explain_parallel_sort_stats                           
+---------------------------------------------------------------------------------
+ Nested Loop Left Join (actual min_rows=30000 rows=30000 max_rows=30000 loops=1)
    ->  Values Scan on "*VALUES*" (actual rows=3 loops=1)
    ->  Gather Merge (actual rows=10000 loops=3)
          Workers Planned: 4
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 1e904a8c5b7..20688561614 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -452,6 +452,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;

From 903c203e7e5f298f927ade97ca03a0e129c31e75 Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sat, 31 Oct 2020 01:47:46 +0100
Subject: [PATCH 1/2] extra_statistics_v1

---
 src/backend/commands/explain.c                | 131 ++++++++++++++----
 src/backend/executor/instrument.c             |  32 ++++-
 src/include/executor/instrument.h             |   4 +
 src/test/regress/expected/partition_prune.out |  36 ++---
 src/test/regress/expected/select_parallel.out |  12 +-
 src/test/regress/sql/partition_prune.sql      |   2 +
 6 files changed, 163 insertions(+), 54 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 43f9b01e83..72dae57ee2 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1568,29 +1568,64 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		min_r = planstate->instrument->min_tuples;
+		double		max_r = planstate->instrument->max_tuples;
+		double		min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
+			if (nodeTag(plan) == T_NestLoop) {
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f min_time=%.3f max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 min_r, rows, max_r, nloops);
+			}
 			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
+			{
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, rows, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual rows=%.0f loops=%.0f)",
+									 rows, nloops);
+			}
 		}
 		else
 		{
-			if (es->timing)
+			if (nodeTag(plan) == T_NestLoop) {
+				if (es->timing) {
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+					ExplainPropertyFloat("Min Time", "s", min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Max Time", "s", max_t_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+			}
+			else
 			{
-				ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
-									 3, es);
+				if (es->timing) {
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
 	else if (es->analyze)
@@ -1599,6 +1634,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1624,39 +1660,78 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		nloops = instrument->nloops;
 			double		startup_ms;
 			double		total_ms;
+			double		min_t_ms;
+			double		max_t_ms;
 			double		rows;
+			double		min_r;
+			double		max_r;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
+			min_t_ms = 1000.0 * planstate->instrument->min_t;
+			max_t_ms = 1000.0 * planstate->instrument->max_t;
 			rows = instrument->ntuples / nloops;
+			min_r = planstate->instrument->min_tuples;
+			max_r = planstate->instrument->max_tuples;
 
 			ExplainOpenWorker(n, es);
 
 			if (es->format == EXPLAIN_FORMAT_TEXT)
 			{
 				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
+				if (nodeTag(plan) == T_NestLoop) {
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f min_time=%.3f  max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 min_r, rows, max_r, nloops);
+				}
 				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
+				{
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, rows, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual rows=%.0f loops=%.0f\n",
+										 rows, nloops);
+				}
 			}
 			else
 			{
-				if (es->timing)
+				if (nodeTag(plan) == T_NestLoop) {
+					if (es->timing) {
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+						ExplainPropertyFloat("Min Time", "ms",
+											 min_t_ms, 3, es);
+						ExplainPropertyFloat("Max Time", "ms",
+											 max_t_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+				}
+				else
 				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
+					if (es->timing) {
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
 			ExplainCloseWorker(n, es);
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index fbedb5aaf6..b0748721c3 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -118,9 +118,8 @@ InstrStopNode(Instrumentation *instr, double nTuples)
 
 /* Finish a run cycle for a plan node */
 void
-InstrEndLoop(Instrumentation *instr)
-{
-	double		totaltime;
+InstrEndLoop(Instrumentation *instr) {
+	double totaltime;
 
 	/* Skip if nothing has happened, or already shut down */
 	if (!instr->running)
@@ -134,7 +133,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+	if (instr->nloops == 0)					/* this is first loop */
+	{
+		if (instr->min_t == 0)
+		{
+			instr->min_t = totaltime;		/* init min_t */
+		}
+		if (instr->min_tuples == 0)
+		{
+			instr->min_tuples = instr->tuplecount;	/* init min_tuples */
+		}
+	}
+	if (instr->min_t > totaltime)
+	{
+		instr->min_t = totaltime;
+	}
+	if (instr->max_t < totaltime)
+	{
+		instr->max_t = totaltime;
+	}
 	instr->ntuples += instr->tuplecount;
+	if (instr->min_tuples > instr->tuplecount)
+	{
+		instr->min_tuples = instr->tuplecount;
+	}
+	if (instr->max_tuples < instr->tuplecount)
+	{
+		instr->max_tuples = instr->tuplecount;
+	}
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 9dc3ecb07d..dbfac349cc 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,7 +66,11 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all loops */
+	double		max_tuples;		/* max counter of produced tuples for all loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 50d2a7e4b9..ba864a5767 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1929,6 +1929,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
@@ -2065,7 +2067,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{0,0,1}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2099,7 +2101,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{0,0,1}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2132,7 +2134,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,3}'::integer[]))
                      ->  Append (actual rows=N loops=N)
@@ -2164,7 +2166,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: N
@@ -2198,7 +2200,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
          Workers Planned: 1
          Workers Launched: N
          ->  Partial Aggregate (actual rows=N loops=N)
-               ->  Nested Loop (actual rows=N loops=N)
+               ->  Nested Loop (actual min_rows=N rows=N max_rows=N loops=N)
                      ->  Parallel Seq Scan on lprt_a a (actual rows=N loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: N
@@ -2441,7 +2443,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
    Update on ab_a1_b1 ab_a1_1
    Update on ab_a1_b2 ab_a1_2
    Update on ab_a1_b3 ab_a1_3
-   ->  Nested Loop (actual rows=0 loops=1)
+   ->  Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2461,7 +2463,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
                      Recheck Cond: (a = 1)
                      ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0 loops=1)
                            Index Cond: (a = 1)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2482,7 +2484,7 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;
                      Heap Blocks: exact=1
                      ->  Bitmap Index Scan on ab_a1_b2_a_idx (actual rows=1 loops=1)
                            Index Cond: (a = 1)
-   ->  Nested Loop (actual rows=0 loops=1)
+   ->  Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
          ->  Append (actual rows=1 loops=1)
                ->  Bitmap Heap Scan on ab_a1_b1 ab_1 (actual rows=0 loops=1)
                      Recheck Cond: (a = 1)
@@ -2523,7 +2525,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
    Update on ab_a1_b3 ab_a1_3
    InitPlan 1 (returns $0)
      ->  Result (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b1 ab_a1_1 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2533,7 +2535,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
                            Filter: (b = $0)
                      ->  Seq Scan on ab_a2_b3 ab_a2_3 (never executed)
                            Filter: (b = $0)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b2 ab_a1_2 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2543,7 +2545,7 @@ update ab_a1 set b = 3 from ab_a2 where ab_a2.b = (select 1);
                            Filter: (b = $0)
                      ->  Seq Scan on ab_a2_b3 ab_a2_3 (never executed)
                            Filter: (b = $0)
-   ->  Nested Loop (actual rows=1 loops=1)
+   ->  Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
          ->  Seq Scan on ab_a1_b3 ab_a1_3 (actual rows=1 loops=1)
          ->  Materialize (actual rows=1 loops=1)
                ->  Append (actual rows=1 loops=1)
@@ -2589,7 +2591,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 > tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=6 loops=1)
+ Nested Loop (actual min_rows=6 rows=6 max_rows=6 loops=1)
    ->  Seq Scan on tbl1 (actual rows=2 loops=1)
    ->  Append (actual rows=3 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2 loops=2)
@@ -2610,7 +2612,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=2 loops=1)
+ Nested Loop (actual min_rows=2 rows=2 max_rows=2 loops=1)
    ->  Seq Scan on tbl1 (actual rows=2 loops=1)
    ->  Append (actual rows=1 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2655,7 +2657,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=23 loops=1)
+ Nested Loop (actual min_rows=23 rows=23 max_rows=23 loops=1)
    ->  Seq Scan on tbl1 (actual rows=5 loops=1)
    ->  Append (actual rows=5 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2 loops=5)
@@ -2676,7 +2678,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=3 loops=1)
+ Nested Loop (actual min_rows=3 rows=3 max_rows=3 loops=1)
    ->  Seq Scan on tbl1 (actual rows=5 loops=1)
    ->  Append (actual rows=1 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2740,7 +2742,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 < tprt.col1;
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
- Nested Loop (actual rows=1 loops=1)
+ Nested Loop (actual min_rows=1 rows=1 max_rows=1 loops=1)
    ->  Seq Scan on tbl1 (actual rows=1 loops=1)
    ->  Append (actual rows=1 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
@@ -2772,7 +2774,7 @@ explain (analyze, costs off, summary off, timing off)
 select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
                             QUERY PLAN                             
 -------------------------------------------------------------------
- Nested Loop (actual rows=0 loops=1)
+ Nested Loop (actual min_rows=0 rows=0 max_rows=0 loops=1)
    ->  Seq Scan on tbl1 (actual rows=1 loops=1)
    ->  Append (actual rows=0 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 9b0c418db7..e8ccd903b4 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -547,10 +547,10 @@ alter table tenk2 set (parallel_workers = 0);
 explain (analyze, timing off, summary off, costs off)
    select count(*) from tenk1, tenk2 where tenk1.hundred > 1
         and tenk2.thousand=0;
-                                QUERY PLAN                                
---------------------------------------------------------------------------
+                                 QUERY PLAN                                  
+-----------------------------------------------------------------------------
  Aggregate (actual rows=1 loops=1)
-   ->  Nested Loop (actual rows=98000 loops=1)
+   ->  Nested Loop (actual min_rows=98000 rows=98000 max_rows=98000 loops=1)
          ->  Seq Scan on tenk2 (actual rows=10 loops=1)
                Filter: (thousand = 0)
                Rows Removed by Filter: 9990
@@ -581,9 +581,9 @@ begin
 end;
 $$;
 select * from explain_parallel_sort_stats();
-                       explain_parallel_sort_stats                        
---------------------------------------------------------------------------
- Nested Loop Left Join (actual rows=30000 loops=1)
+                           explain_parallel_sort_stats                           
+---------------------------------------------------------------------------------
+ Nested Loop Left Join (actual min_rows=30000 rows=30000 max_rows=30000 loops=1)
    ->  Values Scan on "*VALUES*" (actual rows=3 loops=1)
    ->  Gather Merge (actual rows=10000 loops=3)
          Workers Planned: 4
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 1e904a8c5b..2068856161 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -452,6 +452,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
-- 
2.26.2

From 28f3bdd55cd8784d0af4d53a4e88845782e2eaa0 Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sat, 31 Oct 2020 02:07:20 +0100
Subject: [PATCH 2/2] minor tweaks

---
 src/backend/commands/explain.c    | 32 +++++++++++++++----------
 src/backend/executor/instrument.c | 39 ++++++++++++++++---------------
 2 files changed, 40 insertions(+), 31 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 72dae57ee2..fa8deac55a 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1575,7 +1575,8 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
-			if (nodeTag(plan) == T_NestLoop) {
+			if (nodeTag(plan) == T_NestLoop)
+			{
 				if (es->timing)
 					appendStringInfo(es->str,
 									 " (actual time=%.3f..%.3f min_time=%.3f max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
@@ -1599,8 +1600,10 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		}
 		else
 		{
-			if (nodeTag(plan) == T_NestLoop) {
-				if (es->timing) {
+			if (nodeTag(plan) == T_NestLoop)
+			{
+				if (es->timing)
+				{
 					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
 										 3, es);
 					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
@@ -1617,7 +1620,8 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			}
 			else
 			{
-				if (es->timing) {
+				if (es->timing)
+				{
 					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
 										 3, es);
 					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
@@ -1670,18 +1674,19 @@ ExplainNode(PlanState *planstate, List *ancestors,
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
-			min_t_ms = 1000.0 * planstate->instrument->min_t;
-			max_t_ms = 1000.0 * planstate->instrument->max_t;
+			min_t_ms = 1000.0 * instrument->min_t;
+			max_t_ms = 1000.0 * instrument->max_t;
 			rows = instrument->ntuples / nloops;
-			min_r = planstate->instrument->min_tuples;
-			max_r = planstate->instrument->max_tuples;
+			min_r = instrument->min_tuples;
+			max_r = instrument->max_tuples;
 
 			ExplainOpenWorker(n, es);
 
 			if (es->format == EXPLAIN_FORMAT_TEXT)
 			{
 				ExplainIndentText(es);
-				if (nodeTag(plan) == T_NestLoop) {
+				if (nodeTag(plan) == T_NestLoop)
+				{
 					if (es->timing)
 						appendStringInfo(es->str,
 										 "actual time=%.3f..%.3f min_time=%.3f  max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
@@ -1705,8 +1710,10 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			}
 			else
 			{
-				if (nodeTag(plan) == T_NestLoop) {
-					if (es->timing) {
+				if (nodeTag(plan) == T_NestLoop)
+				{
+					if (es->timing)
+					{
 						ExplainPropertyFloat("Actual Startup Time", "ms",
 											 startup_ms, 3, es);
 						ExplainPropertyFloat("Actual Total Time", "ms",
@@ -1723,7 +1730,8 @@ ExplainNode(PlanState *planstate, List *ancestors,
 				}
 				else
 				{
-					if (es->timing) {
+					if (es->timing)
+					{
 						ExplainPropertyFloat("Actual Startup Time", "ms",
 											 startup_ms, 3, es);
 						ExplainPropertyFloat("Actual Total Time", "ms",
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index b0748721c3..0198bb3a5a 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -118,8 +118,9 @@ InstrStopNode(Instrumentation *instr, double nTuples)
 
 /* Finish a run cycle for a plan node */
 void
-InstrEndLoop(Instrumentation *instr) {
-	double totaltime;
+InstrEndLoop(Instrumentation *instr)
+{
+	double		totaltime;
 
 	/* Skip if nothing has happened, or already shut down */
 	if (!instr->running)
@@ -133,34 +134,34 @@ InstrEndLoop(Instrumentation *instr) {
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
-	if (instr->nloops == 0)					/* this is first loop */
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with
+	 * the max, because those are 0 and the non-zero values will get
+	 * updated a couple lines later.
+	 */
+	if (instr->nloops == 0)
 	{
-		if (instr->min_t == 0)
-		{
-			instr->min_t = totaltime;		/* init min_t */
-		}
-		if (instr->min_tuples == 0)
-		{
-			instr->min_tuples = instr->tuplecount;	/* init min_tuples */
-		}
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
 	}
+
 	if (instr->min_t > totaltime)
-	{
 		instr->min_t = totaltime;
-	}
+
 	if (instr->max_t < totaltime)
-	{
 		instr->max_t = totaltime;
-	}
+
 	instr->ntuples += instr->tuplecount;
+
 	if (instr->min_tuples > instr->tuplecount)
-	{
 		instr->min_tuples = instr->tuplecount;
-	}
+
 	if (instr->max_tuples < instr->tuplecount)
-	{
 		instr->max_tuples = instr->tuplecount;
-	}
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
-- 
2.26.2

From 148b0792b8eed1527ee3266e7e627b3c75effb9e Mon Sep 17 00:00:00 2001
From: Ekaterina Sokolova <e.sokolova@postgrespro.ru>
Date: Thu, 12 Nov 2020 22:06:41 +0300
Subject: [PATCH] extra_statistics_v2

---
 src/backend/commands/explain.c                | 141 ++++++++++++++----
 src/backend/executor/instrument.c             |  27 ++++
 src/include/executor/instrument.h             |   6 +
 src/test/regress/expected/explain.out         |   8 +
 src/test/regress/expected/partition_prune.out |   2 +
 src/test/regress/expected/timetz.out          |   8 +-
 src/test/regress/sql/partition_prune.sql      |   2 +
 7 files changed, 161 insertions(+), 33 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 41317f18374..b525b12b1d6 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1568,29 +1568,68 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		min_r = planstate->instrument->min_tuples;
+		double		max_r = planstate->instrument->max_tuples;
+		double		min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
+			if (nloops > 1 && es->verbose)
+			{
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f min_time=%.3f max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f)",
+									 min_r, rows, max_r, nloops);
+			}
 			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
+			{
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, rows, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual rows=%.0f loops=%.0f)",
+									 rows, nloops);
+			}
 		}
 		else
 		{
-			if (es->timing)
+			if (nloops > 1 && es->verbose)
+			{
+				if (es->timing)
+				{
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+					ExplainPropertyFloat("Min Time", "s", min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Max Time", "s", max_t_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+			}
+			else
 			{
-				ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
-									 3, es);
+				if (es->timing)
+				{
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
 	else if (es->analyze)
@@ -1599,6 +1638,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1624,39 +1664,82 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		nloops = instrument->nloops;
 			double		startup_ms;
 			double		total_ms;
+			double		min_t_ms;
+			double		max_t_ms;
 			double		rows;
+			double		min_r;
+			double		max_r;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
+			min_t_ms = 1000.0 * instrument->min_t;
+			max_t_ms = 1000.0 * instrument->max_t;
 			rows = instrument->ntuples / nloops;
+			min_r = instrument->min_tuples;
+			max_r = instrument->max_tuples;
 
 			ExplainOpenWorker(n, es);
 
 			if (es->format == EXPLAIN_FORMAT_TEXT)
 			{
 				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
+				if (nloops > 1)
+				{
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f min_time=%.3f  max_time=%.3f min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, min_t_ms, max_t_ms, min_r, rows, max_r, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual min_rows=%.0f rows=%.0f max_rows=%.0f loops=%.0f\n",
+										 min_r, rows, max_r, nloops);
+				}
 				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
+				{
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, rows, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual rows=%.0f loops=%.0f\n",
+										 rows, nloops);
+				}
 			}
 			else
 			{
-				if (es->timing)
+				if (nloops > 1)
 				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
+					if (es->timing)
+					{
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+						ExplainPropertyFloat("Min Time", "ms",
+											 min_t_ms, 3, es);
+						ExplainPropertyFloat("Max Time", "ms",
+											 max_t_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Min Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Max Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+				}
+				else
+				{
+					if (es->timing)
+					{
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
 			ExplainCloseWorker(n, es);
@@ -3094,7 +3177,7 @@ show_hashagg_info(AggState *aggstate, ExplainState *es)
 			if (aggstate->hash_batches_used > 1)
 			{
 				appendStringInfo(es->str, "  Disk Usage: " UINT64_FORMAT "kB",
-					aggstate->hash_disk_used);
+								 aggstate->hash_disk_used);
 			}
 		}
 
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index fbedb5aaf60..db1be682e1c 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -134,7 +134,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 9dc3ecb07d7..a458b566e0d 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,7 +66,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index dc7ab2ce8bf..aa3955ad1fc 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -341,6 +341,10 @@ select jsonb_pretty(
                                  "string4"                  +
                              ],                             +
                              "Schema": "public",            +
+                             "Max Rows": 0,                 +
+                             "Max Time": 0.0,               +
+                             "Min Rows": 0,                 +
+                             "Min Time": 0.0,               +
                              "Node Type": "Seq Scan",       +
                              "Plan Rows": 0,                +
                              "Plan Width": 0,               +
@@ -383,6 +387,10 @@ select jsonb_pretty(
                          "stringu2",                        +
                          "string4"                          +
                      ],                                     +
+                     "Max Rows": 0,                         +
+                     "Max Time": 0.0,                       +
+                     "Min Rows": 0,                         +
+                     "Min Time": 0.0,                       +
                      "Sort Key": [                          +
                          "tenk1.tenthous"                   +
                      ],                                     +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 50d2a7e4b97..2d8ad48ff09 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1929,6 +1929,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
diff --git a/src/test/regress/expected/timetz.out b/src/test/regress/expected/timetz.out
index 038bb5fa094..5294179aa45 100644

diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 1e904a8c5b7..20688561614 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -452,6 +452,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'actual min_rows=\d+ rows=\d+ max_rows=\d+ loops=\d+',
+				 'actual min_rows=N rows=N max_rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
-- 
2.26.0

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index afc45429ba4..723eccca013 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1589,29 +1589,82 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		total_rows = planstate->instrument->ntuples;
+		double		min_r = planstate->instrument->min_tuples;
+		double		max_r = planstate->instrument->max_tuples;
+		double		min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
+			if (nloops > 1 && es->verbose)
+			{
+				if (es->timing)
+				{
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)\n",
+									 startup_ms, total_ms, rows, nloops);
+					ExplainIndentText(es);
+					appendStringInfo(es->str,
+									 "Loop: min_time=%.3f max_time=%.3f min_rows=%.0f max_rows=%.0f total_rows=%.0f",
+									 min_t_ms, max_t_ms, min_r, max_r, total_rows);
+				}
+				else
+				{
+					appendStringInfo(es->str,
+									 " (actual rows=%.0f loops=%.0f)\n",
+									 rows, nloops);
+					ExplainIndentText(es);
+					appendStringInfo(es->str,
+									 "Loop: min_rows=%.0f max_rows=%.0f total_rows=%.0f",
+									 min_r, max_r, total_rows);
+				}
+			}
 			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
+			{
+				if (es->timing)
+					appendStringInfo(es->str,
+									 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
+									 startup_ms, total_ms, rows, nloops);
+				else
+					appendStringInfo(es->str,
+									 " (actual rows=%.0f loops=%.0f)",
+									 rows, nloops);
+			}
 		}
 		else
 		{
-			if (es->timing)
+			if (nloops > 1 && es->verbose)
+			{
+				if (es->timing)
+				{
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+					ExplainPropertyFloat("Min Time", "s", min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Max Time", "s", max_t_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Min Rows", NULL, min_r, 0, es);
+				ExplainPropertyFloat("Max Rows", NULL, max_r, 0, es);
+				ExplainPropertyFloat("Total Rows", NULL, total_rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+			}
+			else
 			{
-				ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
-									 3, es);
+				if (es->timing)
+				{
+					ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+										 3, es);
+					ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+										 3, es);
+				}
+				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
 	else if (es->analyze)
@@ -1620,6 +1673,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1646,38 +1700,96 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		startup_ms;
 			double		total_ms;
 			double		rows;
+			double		min_t_ms;
+			double		max_t_ms;
+			double		min_r;
+			double		max_r;
+			double		total_rows;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
 			rows = instrument->ntuples / nloops;
+			min_t_ms = 1000.0 * instrument->min_t;
+			max_t_ms = 1000.0 * instrument->max_t;
+			min_r = instrument->min_tuples;
+			max_r = instrument->max_tuples;
+			total_rows = instrument->ntuples;
 
 			ExplainOpenWorker(n, es);
 
 			if (es->format == EXPLAIN_FORMAT_TEXT)
 			{
 				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
+				if (nloops > 1)
+				{
+					if (es->timing)
+					{
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, rows, nloops);
+						ExplainIndentText(es);
+						appendStringInfo(es->str,
+										 "Loop: min_time=%.3f  max_time=%.3f min_rows=%.0f max_rows=%.0f total_rows=%.0f",
+										 min_t_ms, max_t_ms, min_r, max_r, total_rows);
+					}
+					else
+					{
+						appendStringInfo(es->str,
+										 "actual rows=%.0f loops=%.0f\n",
+										 rows, nloops);
+						ExplainIndentText(es);
+						appendStringInfo(es->str,
+										 "Loop: min_rows=%.0f max_rows=%.0f total_rows=%.0f",
+										 min_r, max_r, total_rows);
+					}
+				}
 				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
+				{
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
+										 startup_ms, total_ms, rows, nloops);
+					else
+						appendStringInfo(es->str,
+										 "actual rows=%.0f loops=%.0f\n",
+										 rows, nloops);
+				}
 			}
 			else
 			{
-				if (es->timing)
+				if (nloops > 1)
 				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
+					if (es->timing)
+					{
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+						ExplainPropertyFloat("Min Time", "ms",
+											 min_t_ms, 3, es);
+						ExplainPropertyFloat("Max Time", "ms",
+											 max_t_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Min Rows", NULL, min_r, 0, es);
+					ExplainPropertyFloat("Max Rows", NULL, max_r, 0, es);
+					ExplainPropertyFloat("Total Rows", NULL, total_rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+				}
+				else
+				{
+					if (es->timing)
+					{
+						ExplainPropertyFloat("Actual Startup Time", "ms",
+											 startup_ms, 3, es);
+						ExplainPropertyFloat("Actual Total Time", "ms",
+											 total_ms, 3, es);
+					}
+					ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+					ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
 			ExplainCloseWorker(n, es);
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index 237e13361b5..d2c3e678882 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -134,7 +134,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -167,6 +194,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index aa8eceda5f4..93ba7c83461 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,7 +66,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index dc7ab2ce8bf..0569662ca50 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -341,10 +341,15 @@ select jsonb_pretty(
                                  "string4"                  +
                              ],                             +
                              "Schema": "public",            +
+                             "Max Rows": 0,                 +
+                             "Max Time": 0.0,               +
+                             "Min Rows": 0,                 +
+                             "Min Time": 0.0,               +
                              "Node Type": "Seq Scan",       +
                              "Plan Rows": 0,                +
                              "Plan Width": 0,               +
                              "Total Cost": 0.0,             +
+                             "Total Rows": 0,               +
                              "Actual Rows": 0,              +
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
@@ -383,6 +388,10 @@ select jsonb_pretty(
                          "stringu2",                        +
                          "string4"                          +
                      ],                                     +
+                     "Max Rows": 0,                         +
+                     "Max Time": 0.0,                       +
+                     "Min Rows": 0,                         +
+                     "Min Time": 0.0,                       +
                      "Sort Key": [                          +
                          "tenk1.tenthous"                   +
                      ],                                     +
@@ -390,6 +399,7 @@ select jsonb_pretty(
                      "Plan Rows": 0,                        +
                      "Plan Width": 0,                       +
                      "Total Cost": 0.0,                     +
+                     "Total Rows": 0,                       +
                      "Actual Rows": 0,                      +
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index bde29e38a94..bb979432405 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1957,6 +1957,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop: min_rows=\d+ max_rows=\d+ total_rows=\d+',
+				 'Loop: min_rows=N max_rows=N total_rows=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
@@ -2761,6 +2763,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop: min_rows=2 max_rows=6 total_rows=23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop: min_rows=2 max_rows=2 total_rows=10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop: min_rows=2 max_rows=3 total_rows=11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop: min_rows=1 max_rows=1 total_rows=2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop: min_rows=0 max_rows=1 total_rows=3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop: min_rows=1 max_rows=1 total_rows=2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop: min_rows=0 max_rows=1 total_rows=1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 6ccb52ad1d6..6224e3a4964 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -463,6 +463,8 @@ begin
     loop
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop: min_rows=\d+ max_rows=\d+ total_rows=\d+',
+				 'Loop: min_rows=N max_rows=N total_rows=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
         return next ln;
     end loop;
@@ -652,6 +654,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);

From: "Ekaterina Sokolova" <e.sokolova@postgrespro.ru>
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index b62a76e7e5a..bf8c37baefd 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1615,6 +1615,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		loop_total_rows = planstate->instrument->ntuples;
+		double		loop_min_r = planstate->instrument->min_tuples;
+		double		loop_max_r = planstate->instrument->max_tuples;
+		double		loop_min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		loop_max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
@@ -1626,6 +1631,19 @@ ExplainNode(PlanState *planstate, List *ancestors,
 				appendStringInfo(es->str,
 								 " (actual rows=%.0f loops=%.0f)",
 								 rows, nloops);
+			if (nloops > 1 && es->verbose)
+			{
+                appendStringInfo(es->str, "\n");
+				ExplainIndentText(es);
+				if (es->timing)
+					appendStringInfo(es->str,
+									 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+									 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+				else
+					appendStringInfo(es->str,
+									 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+									 loop_min_r, loop_max_r, loop_total_rows);
+			}
 		}
 		else
 		{
@@ -1635,8 +1653,21 @@ ExplainNode(PlanState *planstate, List *ancestors,
 									 3, es);
 				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
 									 3, es);
+				if (nloops > 1 && es->verbose)
+				{
+					ExplainPropertyFloat("Loop Min Time", "s", loop_min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Loop Max Time", "s", loop_max_t_ms,
+										 3, es);
+				}
 			}
 			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+			if (nloops > 1 && es->verbose)
+			{
+				ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+				ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+				ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+			}
 			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
@@ -1646,6 +1677,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1672,12 +1704,22 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		startup_ms;
 			double		total_ms;
 			double		rows;
+			double		loop_min_t_ms;
+			double		loop_max_t_ms;
+			double		loop_min_r;
+			double		loop_max_r;
+			double		loop_total_rows;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
 			rows = instrument->ntuples / nloops;
+			loop_min_t_ms = 1000.0 * instrument->min_t;
+			loop_max_t_ms = 1000.0 * instrument->max_t;
+			loop_min_r = instrument->min_tuples;
+			loop_max_r = instrument->max_tuples;
+			loop_total_rows = instrument->ntuples;
 
 			ExplainOpenWorker(n, es);
 
@@ -1692,6 +1734,19 @@ ExplainNode(PlanState *planstate, List *ancestors,
 					appendStringInfo(es->str,
 									 "actual rows=%.0f loops=%.0f\n",
 									 rows, nloops);
+				if (nloops > 1)
+				{
+                    appendStringInfo(es->str, "\n");
+					ExplainIndentText(es);
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+										 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+					else
+						appendStringInfo(es->str,
+										 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+										 loop_min_r, loop_max_r, loop_total_rows);
+				}
 			}
 			else
 			{
@@ -1701,8 +1756,21 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										 startup_ms, 3, es);
 					ExplainPropertyFloat("Actual Total Time", "ms",
 										 total_ms, 3, es);
+					if (nloops > 1)
+					{
+						ExplainPropertyFloat("Loop Min Time", "ms",
+											 loop_min_t_ms, 3, es);
+						ExplainPropertyFloat("Loop Max Time", "ms",
+											 loop_max_t_ms, 3, es);
+					}
 				}
 				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				if (nloops > 1)
+				{
+					ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+					ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+					ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+				}
 				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index 237e13361b5..d2c3e678882 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -134,7 +134,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -167,6 +194,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index aa8eceda5f4..93ba7c83461 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,7 +66,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index cda28098baa..b51659d57f3 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -351,8 +351,13 @@ select jsonb_pretty(
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
                              "Async Capable": false,        +
+                             "Loop Max Rows": 0,            +
+                             "Loop Max Time": 0.0,          +
+                             "Loop Min Rows": 0,            +
+                             "Loop Min Time": 0.0,          +
                              "Relation Name": "tenk1",      +
                              "Parallel Aware": true,        +
+                             "Loop Total Rows": 0,          +
                              "Local Hit Blocks": 0,         +
                              "Temp Read Blocks": 0,         +
                              "Actual Total Time": 0.0,      +
@@ -397,7 +402,12 @@ select jsonb_pretty(
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
                      "Async Capable": false,                +
+                     "Loop Max Rows": 0,                    +
+                     "Loop Max Time": 0.0,                  +
+                     "Loop Min Rows": 0,                    +
+                     "Loop Min Time": 0.0,                  +
                      "Parallel Aware": false,               +
+                     "Loop Total Rows": 0,                  +
                      "Sort Space Used": 0,                  +
                      "Local Hit Blocks": 0,                 +
                      "Temp Read Blocks": 0,                 +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 1a7149bfd57..8d87af92593 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1961,6 +1961,10 @@ begin
         ln := regexp_replace(ln, 'Hits: \d+', 'Hits: N');
         ln := regexp_replace(ln, 'Misses: \d+', 'Misses: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
+        ln := regexp_replace(ln, 'Loop min_time: \d+  max_time: \d+  min_rows: \d+  max_rows: \d+  total_rows: \d+',
+                                 'Loop min_time: N  max_time: N  min_rows: N  max_rows: N  total_rows: N');
+        ln := regexp_replace(ln, 'Loop min_rows: \d+  max_rows: \d+  total_rows: \d+',
+                                 'Loop min_rows: N  max_rows: N  total_rows: N');
         return next ln;
     end loop;
 end;
@@ -2718,6 +2722,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop min_rows: 2  max_rows: 6  total_rows: 23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop min_rows: 2  max_rows: 2  total_rows: 10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop min_rows: 2  max_rows: 3  total_rows: 11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop min_rows: 0  max_rows: 1  total_rows: 3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop min_rows: 0  max_rows: 1  total_rows: 1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 247264f93b7..c1268e23f27 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -467,6 +467,10 @@ begin
         ln := regexp_replace(ln, 'Hits: \d+', 'Hits: N');
         ln := regexp_replace(ln, 'Misses: \d+', 'Misses: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
+        ln := regexp_replace(ln, 'Loop min_time: \d+  max_time: \d+  min_rows: \d+  max_rows: \d+  total_rows: \d+',
+                                 'Loop min_time: N  max_time: N  min_rows: N  max_rows: N  total_rows: N');
+        ln := regexp_replace(ln, 'Loop min_rows: \d+  max_rows: \d+  total_rows: \d+',
+                                 'Loop min_rows: N  max_rows: N  total_rows: N');
         return next ln;
     end loop;
 end;
@@ -657,6 +661,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);

Author: Ekaterina Sokolova <e.sokolova@postgrespro.ru>

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 10644dfac44..9c71819deb2 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1611,6 +1611,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
 		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
 		double		rows = planstate->instrument->ntuples / nloops;
+		double		loop_total_rows = planstate->instrument->ntuples;
+		double		loop_min_r = planstate->instrument->min_tuples;
+		double		loop_max_r = planstate->instrument->max_tuples;
+		double		loop_min_t_ms = 1000.0 * planstate->instrument->min_t;
+		double		loop_max_t_ms = 1000.0 * planstate->instrument->max_t;
 
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 		{
@@ -1622,6 +1627,19 @@ ExplainNode(PlanState *planstate, List *ancestors,
 				appendStringInfo(es->str,
 								 " (actual rows=%.0f loops=%.0f)",
 								 rows, nloops);
+			if (nloops > 1 && es->verbose)
+			{
+				appendStringInfo(es->str, "\n");
+				ExplainIndentText(es);
+				if (es->timing)
+					appendStringInfo(es->str,
+									 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+									 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+				else
+					appendStringInfo(es->str,
+									 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+									 loop_min_r, loop_max_r, loop_total_rows);
+			}
 		}
 		else
 		{
@@ -1631,8 +1649,21 @@ ExplainNode(PlanState *planstate, List *ancestors,
 									 3, es);
 				ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
 									 3, es);
+				if (nloops > 1 && es->verbose)
+				{
+					ExplainPropertyFloat("Loop Min Time", "s", loop_min_t_ms,
+										 3, es);
+					ExplainPropertyFloat("Loop Max Time", "s", loop_max_t_ms,
+										 3, es);
+				}
 			}
 			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+			if (nloops > 1 && es->verbose)
+			{
+				ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+				ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+				ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+			}
 			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 		}
 	}
@@ -1642,6 +1673,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1668,12 +1700,22 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			double		startup_ms;
 			double		total_ms;
 			double		rows;
+			double		loop_min_t_ms;
+			double		loop_max_t_ms;
+			double		loop_min_r;
+			double		loop_max_r;
+			double		loop_total_rows;
 
 			if (nloops <= 0)
 				continue;
 			startup_ms = 1000.0 * instrument->startup / nloops;
 			total_ms = 1000.0 * instrument->total / nloops;
 			rows = instrument->ntuples / nloops;
+			loop_min_t_ms = 1000.0 * instrument->min_t;
+			loop_max_t_ms = 1000.0 * instrument->max_t;
+			loop_min_r = instrument->min_tuples;
+			loop_max_r = instrument->max_tuples;
+			loop_total_rows = instrument->ntuples;
 
 			ExplainOpenWorker(n, es);
 
@@ -1688,6 +1730,19 @@ ExplainNode(PlanState *planstate, List *ancestors,
 					appendStringInfo(es->str,
 									 "actual rows=%.0f loops=%.0f\n",
 									 rows, nloops);
+				if (nloops > 1)
+				{
+					appendStringInfo(es->str, "\n");
+					ExplainIndentText(es);
+					if (es->timing)
+						appendStringInfo(es->str,
+										 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+										 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+					else
+						appendStringInfo(es->str,
+										 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+										 loop_min_r, loop_max_r, loop_total_rows);
+				}
 			}
 			else
 			{
@@ -1697,8 +1752,21 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										 startup_ms, 3, es);
 					ExplainPropertyFloat("Actual Total Time", "ms",
 										 total_ms, 3, es);
+					if (nloops > 1)
+					{
+						ExplainPropertyFloat("Loop Min Time", "ms",
+											 loop_min_t_ms, 3, es);
+						ExplainPropertyFloat("Loop Max Time", "ms",
+											 loop_max_t_ms, 3, es);
+					}
 				}
 				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+				if (nloops > 1)
+				{
+					ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+					ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+					ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+				}
 				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 			}
 
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index 2b106d8473c..6588ce2db6a 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -153,7 +153,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -186,6 +213,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 2f9905b7c8e..e2ff330b8f1 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -79,7 +79,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index 1734dfee8cc..275cdb37672 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -354,8 +354,13 @@ select jsonb_pretty(
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
                              "Async Capable": false,        +
+                             "Loop Max Rows": 0,            +
+                             "Loop Max Time": 0.0,          +
+                             "Loop Min Rows": 0,            +
+                             "Loop Min Time": 0.0,          +
                              "Relation Name": "tenk1",      +
                              "Parallel Aware": true,        +
+                             "Loop Total Rows": 0,          +
                              "Local Hit Blocks": 0,         +
                              "Temp Read Blocks": 0,         +
                              "Actual Total Time": 0.0,      +
@@ -400,7 +405,12 @@ select jsonb_pretty(
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
                      "Async Capable": false,                +
+                     "Loop Max Rows": 0,                    +
+                     "Loop Max Time": 0.0,                  +
+                     "Loop Min Rows": 0,                    +
+                     "Loop Min Time": 0.0,                  +
                      "Parallel Aware": false,               +
+                     "Loop Total Rows": 0,                  +
                      "Sort Space Used": 0,                  +
                      "Local Hit Blocks": 0,                 +
                      "Temp Read Blocks": 0,                 +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c779..0e1242c089a 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2715,6 +2715,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop min_rows: 2  max_rows: 6  total_rows: 23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop min_rows: 2  max_rows: 2  total_rows: 10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop min_rows: 2  max_rows: 3  total_rows: 11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop min_rows: 0  max_rows: 1  total_rows: 3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop min_rows: 0  max_rows: 1  total_rows: 1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index d70bd8610cb..d5ba8d6f386 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -654,6 +654,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);

From e9dc405c55507b6c93a0e66434c5757254e95d54 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 15 Apr 2021 11:55:09 -0500
Subject: [PATCH 1/3] explain.c: refactor ExplainNode()

---
 src/backend/commands/explain.c | 110 ++++++++++++++-------------------
 1 file changed, 47 insertions(+), 63 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 891ad0e717..db99739cc5 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -118,6 +118,8 @@ static void show_instrumentation_count(const char *qlabel, int which,
 									   PlanState *planstate, ExplainState *es);
 static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
 static void show_eval_params(Bitmapset *bms_params, ExplainState *es);
+static void show_loop_info(Instrumentation *instrument, bool isworker,
+		ExplainState *es);
 static const char *explain_get_index_name(Oid indexId);
 static void show_buffer_usage(ExplainState *es, const BufferUsage *usage,
 							  bool planning);
@@ -1609,36 +1611,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 	if (es->analyze &&
 		planstate->instrument && planstate->instrument->nloops > 0)
-	{
-		double		nloops = planstate->instrument->nloops;
-		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
-		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
-		double		rows = planstate->instrument->ntuples / nloops;
-
-		if (es->format == EXPLAIN_FORMAT_TEXT)
-		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
-			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
-		}
-		else
-		{
-			if (es->timing)
-			{
-				ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
-									 3, es);
-			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-		}
-	}
+		show_loop_info(planstate->instrument, false, es);
 	else if (es->analyze)
 	{
 		if (es->format == EXPLAIN_FORMAT_TEXT)
@@ -1667,44 +1640,14 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		for (int n = 0; n < w->num_workers; n++)
 		{
 			Instrumentation *instrument = &w->instrument[n];
-			double		nloops = instrument->nloops;
-			double		startup_ms;
-			double		total_ms;
-			double		rows;
 
-			if (nloops <= 0)
+			if (instrument->nloops <= 0)
 				continue;
-			startup_ms = 1000.0 * instrument->startup / nloops;
-			total_ms = 1000.0 * instrument->total / nloops;
-			rows = instrument->ntuples / nloops;
 
 			ExplainOpenWorker(n, es);
-
+			show_loop_info(instrument, true, es);
 			if (es->format == EXPLAIN_FORMAT_TEXT)
-			{
-				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
-				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
-			}
-			else
-			{
-				if (es->timing)
-				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
-				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-			}
-
+				appendStringInfoChar(es->str, '\n');
 			ExplainCloseWorker(n, es);
 		}
 	}
@@ -4030,6 +3973,47 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 		ExplainCloseGroup("Target Tables", "Target Tables", false, es);
 }
 
+void
+show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
+{
+	double		nloops = instrument->nloops;
+	double		startup_ms = 1000.0 * instrument->startup / nloops;
+	double		total_ms = 1000.0 * instrument->total / nloops;
+	double		rows = instrument->ntuples / nloops;
+
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		if (isworker)
+			ExplainIndentText(es);
+		else
+			appendStringInfo(es->str, " (");
+
+		if (es->timing)
+			appendStringInfo(es->str,
+							 "actual time=%.3f..%.3f rows=%.0f loops=%.0f",
+							 startup_ms, total_ms, rows, nloops);
+		else
+			appendStringInfo(es->str,
+							 "actual rows=%.0f loops=%.0f",
+							 rows, nloops);
+
+		if (!isworker)
+			appendStringInfoChar(es->str, ')');
+	}
+	else
+	{
+		if (es->timing)
+		{
+			ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
+								 3, es);
+			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
+								 3, es);
+		}
+		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+		ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+	}
+}
+
 /*
  * Explain the constituent plans of an Append, MergeAppend,
  * BitmapAnd, or BitmapOr node.
-- 
2.17.0

From bd6f2fc1073a3e5d9c982ea681094856f67bf30a Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 30 Sep 2021 01:22:02 -0500
Subject: [PATCH 2/3] Re: [PATCH] Add extra statistics to explain for Nested
 Loop

Aug 17 Ekaterina Sokol
---
 src/backend/commands/explain.c                | 37 +++++++++++
 src/backend/executor/instrument.c             | 31 +++++++++
 src/include/executor/instrument.h             |  6 ++
 src/test/regress/expected/explain.out         | 10 +++
 src/test/regress/expected/partition_prune.out | 66 +++++++++++++++++++
 src/test/regress/sql/partition_prune.sql      |  7 ++
 6 files changed, 157 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index db99739cc5..428a073099 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1618,6 +1618,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -3980,6 +3981,11 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 	double		startup_ms = 1000.0 * instrument->startup / nloops;
 	double		total_ms = 1000.0 * instrument->total / nloops;
 	double		rows = instrument->ntuples / nloops;
+	double		loop_total_rows = instrument->ntuples;
+	double		loop_min_r = instrument->min_tuples;
+	double		loop_max_r = instrument->max_tuples;
+	double		loop_min_t_ms = 1000.0 * instrument->min_t;
+	double		loop_max_t_ms = 1000.0 * instrument->max_t;
 
 	if (es->format == EXPLAIN_FORMAT_TEXT)
 	{
@@ -3999,6 +4005,20 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 
 		if (!isworker)
 			appendStringInfoChar(es->str, ')');
+
+		if (nloops > 1 && es->verbose)
+		{
+			appendStringInfo(es->str, "\n");
+			ExplainIndentText(es);
+			if (es->timing)
+				appendStringInfo(es->str,
+								 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+								 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+			else
+				appendStringInfo(es->str,
+								 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+								 loop_min_r, loop_max_r, loop_total_rows);
+		}
 	}
 	else
 	{
@@ -4009,7 +4029,24 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
 								 3, es);
 		}
+
+		if (nloops > 1 && es->verbose)
+		{
+			ExplainPropertyFloat("Loop Min Time", "s", loop_min_t_ms,
+								 3, es);
+			ExplainPropertyFloat("Loop Max Time", "s", loop_max_t_ms,
+								 3, es);
+		}
+
 		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+
+		if (nloops > 1 && es->verbose)
+		{
+			ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+			ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+			ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+		}
+
 		ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 	}
 }
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index 2b106d8473..6588ce2db6 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -153,7 +153,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -186,6 +213,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 1f3aa733ec..d0af28b0b8 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -79,7 +79,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # tuples removed by scanqual or joinqual OR
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index 1734dfee8c..275cdb3767 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -354,8 +354,13 @@ select jsonb_pretty(
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
                              "Async Capable": false,        +
+                             "Loop Max Rows": 0,            +
+                             "Loop Max Time": 0.0,          +
+                             "Loop Min Rows": 0,            +
+                             "Loop Min Time": 0.0,          +
                              "Relation Name": "tenk1",      +
                              "Parallel Aware": true,        +
+                             "Loop Total Rows": 0,          +
                              "Local Hit Blocks": 0,         +
                              "Temp Read Blocks": 0,         +
                              "Actual Total Time": 0.0,      +
@@ -400,7 +405,12 @@ select jsonb_pretty(
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
                      "Async Capable": false,                +
+                     "Loop Max Rows": 0,                    +
+                     "Loop Max Time": 0.0,                  +
+                     "Loop Min Rows": 0,                    +
+                     "Loop Min Time": 0.0,                  +
                      "Parallel Aware": false,               +
+                     "Loop Total Rows": 0,                  +
                      "Sort Space Used": 0,                  +
                      "Local Hit Blocks": 0,                 +
                      "Temp Read Blocks": 0,                 +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c77..0e1242c089 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2715,6 +2715,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop min_rows: 2  max_rows: 6  total_rows: 23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop min_rows: 2  max_rows: 2  total_rows: 10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop min_rows: 2  max_rows: 3  total_rows: 11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop min_rows: 0  max_rows: 1  total_rows: 3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop min_rows: 0  max_rows: 1  total_rows: 1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index d70bd8610c..d5ba8d6f38 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -654,6 +654,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
-- 
2.17.0

From b7c5c53a210ecf1895e70d206f1d67a9e4f13163 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 30 Sep 2021 01:58:11 -0500
Subject: [PATCH 3/3] Justin's changes

---
 src/backend/commands/explain.c                | 24 +++++++++----------
 src/test/regress/expected/partition_prune.out | 14 +++++------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 428a073099..756051864c 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -4008,15 +4008,16 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 
 		if (nloops > 1 && es->verbose)
 		{
-			appendStringInfo(es->str, "\n");
+			appendStringInfoChar(es->str, '\n');
 			ExplainIndentText(es);
+
 			if (es->timing)
 				appendStringInfo(es->str,
-								 "Loop min_time: %.3f  max_time: %.3f  min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
-								 loop_min_t_ms, loop_max_t_ms, loop_min_r, loop_max_r, loop_total_rows);
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f  Min Time: %.3f  Max Time: %.3f",
+								 loop_min_r, loop_max_r, loop_total_rows, loop_min_t_ms, loop_max_t_ms);
 			else
 				appendStringInfo(es->str,
-								 "Loop min_rows: %.0f  max_rows: %.0f  total_rows: %.0f",
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f",
 								 loop_min_r, loop_max_r, loop_total_rows);
 		}
 	}
@@ -4028,14 +4029,13 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 								 3, es);
 			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
 								 3, es);
-		}
-
-		if (nloops > 1 && es->verbose)
-		{
-			ExplainPropertyFloat("Loop Min Time", "s", loop_min_t_ms,
-								 3, es);
-			ExplainPropertyFloat("Loop Max Time", "s", loop_max_t_ms,
-								 3, es);
+			if (nloops > 1 && es->verbose)
+			{
+				ExplainPropertyFloat("Loop Min Time", "ms", loop_min_t_ms,
+									 3, es);
+				ExplainPropertyFloat("Loop Max Time", "ms", loop_max_t_ms,
+									 3, es);
+			}
 		}
 
 		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 0e1242c089..d9d77090dc 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2725,17 +2725,17 @@ select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
    ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
          Output: tbl1.col1
    ->  Append (actual rows=5 loops=5)
-         Loop min_rows: 2  max_rows: 6  total_rows: 23
+         Loop Min Rows: 2  Max Rows: 6  Total Rows: 23
          ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
-               Loop min_rows: 2  max_rows: 2  total_rows: 10
+               Loop Min Rows: 2  Max Rows: 2  Total Rows: 10
                Output: tprt_1.col1
                Index Cond: (tprt_1.col1 < tbl1.col1)
          ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
-               Loop min_rows: 2  max_rows: 3  total_rows: 11
+               Loop Min Rows: 2  Max Rows: 3  Total Rows: 11
                Output: tprt_2.col1
                Index Cond: (tprt_2.col1 < tbl1.col1)
          ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
-               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
                Output: tprt_3.col1
                Index Cond: (tprt_3.col1 < tbl1.col1)
          ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
@@ -2758,16 +2758,16 @@ select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
    ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
          Output: tbl1.col1
    ->  Append (actual rows=1 loops=5)
-         Loop min_rows: 0  max_rows: 1  total_rows: 3
+         Loop Min Rows: 0  Max Rows: 1  Total Rows: 3
          ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
                Output: tprt_1.col1
                Index Cond: (tprt_1.col1 = tbl1.col1)
          ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
-               Loop min_rows: 1  max_rows: 1  total_rows: 2
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
                Output: tprt_2.col1
                Index Cond: (tprt_2.col1 = tbl1.col1)
          ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
-               Loop min_rows: 0  max_rows: 1  total_rows: 1
+               Loop Min Rows: 0  Max Rows: 1  Total Rows: 1
                Output: tprt_3.col1
                Index Cond: (tprt_3.col1 = tbl1.col1)
          ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
-- 
2.17.0

From: Ekaterina Sokolova <e.sokolova@postgrespro.ru>
Subject: [PATCH] Add extra statistics to explain for Nested Loop

For some distributions of data in tables, different loops in nested loop
joins can take different time and process different amounts of entries.
It makes average statistics returned by explain analyze not very useful for DBA.

This patch add collecting of min, max and total statistics for time and rows
across all loops to EXPLAIN ANALYSE. You need to set the VERBOSE flag to display
this information. The patch contains regression tests.

Example of results in TEXT format:
   ->  Append (actual rows=5 loops=5)
         Loop Min Rows: 2  Max Rows: 6  Total Rows: 23

Reviewed-by: Lukas Fittl, Justin Pryzby, Yugo Nagata, Julien Rouhaud.

---
 src/backend/commands/explain.c                | 147 +++++++++++++++-----------
 src/backend/executor/instrument.c             |  31 ++++++
 src/include/executor/instrument.h             |   6 ++
 src/test/regress/expected/explain.out         |  10 ++
 src/test/regress/expected/partition_prune.out | 117 ++++++++++++++++++++
 src/test/regress/sql/partition_prune.sql      |  32 ++++++
 6 files changed, 280 insertions(+), 63 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 10644dfac44..458f37c3fc6 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -118,6 +118,8 @@ static void show_instrumentation_count(const char *qlabel, int which,
 									   PlanState *planstate, ExplainState *es);
 static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
 static void show_eval_params(Bitmapset *bms_params, ExplainState *es);
+static void show_loop_info(Instrumentation *instrument, bool isworker,
+						   ExplainState *es);
 static const char *explain_get_index_name(Oid indexId);
 static void show_buffer_usage(ExplainState *es, const BufferUsage *usage,
 							  bool planning);
@@ -1606,42 +1608,14 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 	if (es->analyze &&
 		planstate->instrument && planstate->instrument->nloops > 0)
-	{
-		double		nloops = planstate->instrument->nloops;
-		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
-		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
-		double		rows = planstate->instrument->ntuples / nloops;
-
-		if (es->format == EXPLAIN_FORMAT_TEXT)
-		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
-			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
-		}
-		else
-		{
-			if (es->timing)
-			{
-				ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
-									 3, es);
-			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-		}
-	}
+		show_loop_info(planstate->instrument, false, es);
 	else if (es->analyze)
 	{
 		if (es->format == EXPLAIN_FORMAT_TEXT)
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -1664,44 +1638,14 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		for (int n = 0; n < w->num_workers; n++)
 		{
 			Instrumentation *instrument = &w->instrument[n];
-			double		nloops = instrument->nloops;
-			double		startup_ms;
-			double		total_ms;
-			double		rows;
 
-			if (nloops <= 0)
+			if (instrument->nloops <= 0)
 				continue;
-			startup_ms = 1000.0 * instrument->startup / nloops;
-			total_ms = 1000.0 * instrument->total / nloops;
-			rows = instrument->ntuples / nloops;
 
 			ExplainOpenWorker(n, es);
-
+			show_loop_info(instrument, true, es);
 			if (es->format == EXPLAIN_FORMAT_TEXT)
-			{
-				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
-				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
-			}
-			else
-			{
-				if (es->timing)
-				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
-				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-			}
-
+				appendStringInfoChar(es->str, '\n');
 			ExplainCloseWorker(n, es);
 		}
 	}
@@ -3995,6 +3939,83 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 		ExplainCloseGroup("Target Tables", "Target Tables", false, es);
 }
 
+void
+show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
+{
+	double		nloops = instrument->nloops;
+	double		startup_ms = 1000.0 * instrument->startup / nloops;
+	double		total_ms = 1000.0 * instrument->total / nloops;
+	double		rows = instrument->ntuples / nloops;
+	double		loop_total_rows = instrument->ntuples;
+	double		loop_min_r = instrument->min_tuples;
+	double		loop_max_r = instrument->max_tuples;
+	double		loop_min_t_ms = 1000.0 * instrument->min_t;
+	double		loop_max_t_ms = 1000.0 * instrument->max_t;
+
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		if (isworker)
+			ExplainIndentText(es);
+		else
+			appendStringInfo(es->str, " (");
+
+		if (es->timing)
+			appendStringInfo(es->str,
+							 "actual time=%.3f..%.3f rows=%.0f loops=%.0f",
+							 startup_ms, total_ms, rows, nloops);
+		else
+			appendStringInfo(es->str,
+							 "actual rows=%.0f loops=%.0f",
+							 rows, nloops);
+
+		if (!isworker)
+			appendStringInfoChar(es->str, ')');
+
+		if (nloops > 1 && es->verbose)
+		{
+			appendStringInfoChar(es->str, '\n');
+			ExplainIndentText(es);
+
+			if (es->timing)
+				appendStringInfo(es->str,
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f  Min Time: %.3f  Max Time: %.3f",
+								 loop_min_r, loop_max_r, loop_total_rows, loop_min_t_ms, loop_max_t_ms);
+			else
+				appendStringInfo(es->str,
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f",
+								 loop_min_r, loop_max_r, loop_total_rows);
+		}
+	}
+	else
+	{
+		if (es->timing)
+		{
+			ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
+								 3, es);
+			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
+								 3, es);
+			if (nloops > 1 && es->verbose)
+			{
+				ExplainPropertyFloat("Loop Min Time", "ms", loop_min_t_ms,
+									 3, es);
+				ExplainPropertyFloat("Loop Max Time", "ms", loop_max_t_ms,
+									 3, es);
+			}
+		}
+
+		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+
+		if (nloops > 1 && es->verbose)
+		{
+			ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+			ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+			ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+		}
+
+		ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+	}
+}
+
 /*
  * Explain the constituent plans of an Append, MergeAppend,
  * BitmapAnd, or BitmapOr node.
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index 2b106d8473c..a49308ed126 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -153,7 +153,34 @@ InstrEndLoop(Instrumentation *instr)
 
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->nloops == 0)
+	{
+		instr->min_t = totaltime;
+		instr->min_tuples = instr->tuplecount;
+	}
+
+	if (instr->min_t > totaltime)
+		instr->min_t = totaltime;
+
+	if (instr->max_t < totaltime)
+		instr->max_t = totaltime;
+
 	instr->ntuples += instr->tuplecount;
+
+	if (instr->min_tuples > instr->tuplecount)
+		instr->min_tuples = instr->tuplecount;
+
+	if (instr->max_tuples < instr->tuplecount)
+		instr->max_tuples = instr->tuplecount;
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -186,6 +213,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 2f9905b7c8e..e2ff330b8f1 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -79,7 +79,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index 1734dfee8cc..275cdb37672 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -354,8 +354,13 @@ select jsonb_pretty(
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
                              "Async Capable": false,        +
+                             "Loop Max Rows": 0,            +
+                             "Loop Max Time": 0.0,          +
+                             "Loop Min Rows": 0,            +
+                             "Loop Min Time": 0.0,          +
                              "Relation Name": "tenk1",      +
                              "Parallel Aware": true,        +
+                             "Loop Total Rows": 0,          +
                              "Local Hit Blocks": 0,         +
                              "Temp Read Blocks": 0,         +
                              "Actual Total Time": 0.0,      +
@@ -400,7 +405,12 @@ select jsonb_pretty(
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
                      "Async Capable": false,                +
+                     "Loop Max Rows": 0,                    +
+                     "Loop Max Time": 0.0,                  +
+                     "Loop Min Rows": 0,                    +
+                     "Loop Min Time": 0.0,                  +
                      "Parallel Aware": false,               +
+                     "Loop Total Rows": 0,                  +
                      "Sort Space Used": 0,                  +
                      "Local Hit Blocks": 0,                 +
                      "Temp Read Blocks": 0,                 +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c779..18617b9e206 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1962,6 +1962,24 @@ begin
     end loop;
 end;
 $$;
+create function explain_verbose_parallel_append(text) returns setof text
+language plpgsql as
+$$
+declare
+    ln text;
+begin
+    for ln in
+        execute format('explain (analyze, verbose, costs off, summary off, timing off) %s',
+            $1)
+    loop
+        ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
+        ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop Min Rows: \d+  Max Rows: \d+  Total Rows: \d+',
+                                 'Loop Min Rows: N  Max Rows: N  Total Rows: N');
+        return next ln;
+    end loop;
+end;
+$$;
 prepare ab_q4 (int, int) as
 select avg(a) from ab where a between $1 and $2 and b < 4;
 -- Encourage use of parallel plans
@@ -2218,6 +2236,39 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
 (28 rows)
 
+-- Tests for extra statistics
+create table lprt_b (b int not null);
+insert into lprt_b select generate_series(1,20);
+select explain_verbose_parallel_append('select * from lprt_a join lprt_b on a != b');
+                       explain_verbose_parallel_append                        
+------------------------------------------------------------------------------
+ Nested Loop (actual rows=N loops=N)
+   Output: lprt_a.a, lprt_b.b
+   Join Filter: (lprt_a.a <> lprt_b.b)
+   Rows Removed by Join Filter: 4
+   ->  Gather (actual rows=N loops=N)
+         Output: lprt_b.b
+         Workers Planned: 2
+         Workers Launched: N
+         ->  Parallel Seq Scan on public.lprt_b (actual rows=N loops=N)
+               Loop Min Rows: N  Max Rows: N  Total Rows: N
+               Output: lprt_b.b
+               Worker 0:  actual rows=N loops=N
+               Worker 1:  actual rows=N loops=N
+   ->  Materialize (actual rows=N loops=N)
+         Loop Min Rows: N  Max Rows: N  Total Rows: N
+         Output: lprt_a.a
+         ->  Gather (actual rows=N loops=N)
+               Output: lprt_a.a
+               Workers Planned: 1
+               Workers Launched: N
+               ->  Parallel Seq Scan on public.lprt_a (actual rows=N loops=N)
+                     Loop Min Rows: N  Max Rows: N  Total Rows: N
+                     Output: lprt_a.a
+                     Worker 0:  actual rows=N loops=N
+(24 rows)
+
+drop table lprt_b;
 delete from lprt_a where a = 1;
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
                                      explain_parallel_append                                     
@@ -2715,6 +2766,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop Min Rows: 2  Max Rows: 6  Total Rows: 23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop Min Rows: 2  Max Rows: 2  Total Rows: 10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop Min Rows: 2  Max Rows: 3  Total Rows: 11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop Min Rows: 0  Max Rows: 1  Total Rows: 3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop Min Rows: 0  Max Rows: 1  Total Rows: 1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index d70bd8610cb..68110e20eeb 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -469,6 +469,25 @@ begin
 end;
 $$;
 
+create function explain_verbose_parallel_append(text) returns setof text
+language plpgsql as
+$$
+declare
+    ln text;
+begin
+    for ln in
+        execute format('explain (analyze, verbose, costs off, summary off, timing off) %s',
+            $1)
+    loop
+        ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
+        ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop Min Rows: \d+  Max Rows: \d+  Total Rows: \d+',
+                                 'Loop Min Rows: N  Max Rows: N  Total Rows: N');
+        return next ln;
+    end loop;
+end;
+$$;
+
 prepare ab_q4 (int, int) as
 select avg(a) from ab where a between $1 and $2 and b < 4;
 
@@ -528,6 +547,12 @@ insert into lprt_a values(3),(3);
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 3)');
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
 
+-- Tests for extra statistics
+create table lprt_b (b int not null);
+insert into lprt_b select generate_series(1,20);
+select explain_verbose_parallel_append('select * from lprt_a join lprt_b on a != b');
+drop table lprt_b;
+
 delete from lprt_a where a = 1;
 
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
@@ -654,6 +679,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);

From 0dec500a0ed934d5d2038cb087ba6a605cafcdef Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 15 Apr 2021 11:55:09 -0500
Subject: [PATCH 1/2] explain.c: refactor ExplainNode()

---
 src/backend/commands/explain.c | 110 ++++++++++++++-------------------
 1 file changed, 47 insertions(+), 63 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index cb13227db1f..06e089a1220 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -118,6 +118,8 @@ static void show_instrumentation_count(const char *qlabel, int which,
 									   PlanState *planstate, ExplainState *es);
 static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
 static void show_eval_params(Bitmapset *bms_params, ExplainState *es);
+static void show_loop_info(Instrumentation *instrument, bool isworker,
+		ExplainState *es);
 static const char *explain_get_index_name(Oid indexId);
 static void show_buffer_usage(ExplainState *es, const BufferUsage *usage,
 							  bool planning);
@@ -1615,36 +1617,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 	if (es->analyze &&
 		planstate->instrument && planstate->instrument->nloops > 0)
-	{
-		double		nloops = planstate->instrument->nloops;
-		double		startup_ms = 1000.0 * planstate->instrument->startup / nloops;
-		double		total_ms = 1000.0 * planstate->instrument->total / nloops;
-		double		rows = planstate->instrument->ntuples / nloops;
-
-		if (es->format == EXPLAIN_FORMAT_TEXT)
-		{
-			if (es->timing)
-				appendStringInfo(es->str,
-								 " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
-								 startup_ms, total_ms, rows, nloops);
-			else
-				appendStringInfo(es->str,
-								 " (actual rows=%.0f loops=%.0f)",
-								 rows, nloops);
-		}
-		else
-		{
-			if (es->timing)
-			{
-				ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
-									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
-									 3, es);
-			}
-			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-			ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-		}
-	}
+		show_loop_info(planstate->instrument, false, es);
 	else if (es->analyze)
 	{
 		if (es->format == EXPLAIN_FORMAT_TEXT)
@@ -1673,44 +1646,14 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		for (int n = 0; n < w->num_workers; n++)
 		{
 			Instrumentation *instrument = &w->instrument[n];
-			double		nloops = instrument->nloops;
-			double		startup_ms;
-			double		total_ms;
-			double		rows;
 
-			if (nloops <= 0)
+			if (instrument->nloops <= 0)
 				continue;
-			startup_ms = 1000.0 * instrument->startup / nloops;
-			total_ms = 1000.0 * instrument->total / nloops;
-			rows = instrument->ntuples / nloops;
 
 			ExplainOpenWorker(n, es);
-
+			show_loop_info(instrument, true, es);
 			if (es->format == EXPLAIN_FORMAT_TEXT)
-			{
-				ExplainIndentText(es);
-				if (es->timing)
-					appendStringInfo(es->str,
-									 "actual time=%.3f..%.3f rows=%.0f loops=%.0f\n",
-									 startup_ms, total_ms, rows, nloops);
-				else
-					appendStringInfo(es->str,
-									 "actual rows=%.0f loops=%.0f\n",
-									 rows, nloops);
-			}
-			else
-			{
-				if (es->timing)
-				{
-					ExplainPropertyFloat("Actual Startup Time", "ms",
-										 startup_ms, 3, es);
-					ExplainPropertyFloat("Actual Total Time", "ms",
-										 total_ms, 3, es);
-				}
-				ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
-				ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
-			}
-
+				appendStringInfoChar(es->str, '\n');
 			ExplainCloseWorker(n, es);
 		}
 	}
@@ -4039,6 +3982,47 @@ show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
 		ExplainCloseGroup("Target Tables", "Target Tables", false, es);
 }
 
+void
+show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
+{
+	double		nloops = instrument->nloops;
+	double		startup_ms = 1000.0 * instrument->startup / nloops;
+	double		total_ms = 1000.0 * instrument->total / nloops;
+	double		rows = instrument->ntuples / nloops;
+
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		if (isworker)
+			ExplainIndentText(es);
+		else
+			appendStringInfo(es->str, " (");
+
+		if (es->timing)
+			appendStringInfo(es->str,
+							 "actual time=%.3f..%.3f rows=%.0f loops=%.0f",
+							 startup_ms, total_ms, rows, nloops);
+		else
+			appendStringInfo(es->str,
+							 "actual rows=%.0f loops=%.0f",
+							 rows, nloops);
+
+		if (!isworker)
+			appendStringInfoChar(es->str, ')');
+	}
+	else
+	{
+		if (es->timing)
+		{
+			ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
+								 3, es);
+			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
+								 3, es);
+		}
+		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+		ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
+	}
+}
+
 /*
  * Explain the constituent plans of an Append, MergeAppend,
  * BitmapAnd, or BitmapOr node.
-- 
2.17.1

From e0d92f2c112002bbacaae7abb747ea618d7fbd93 Mon Sep 17 00:00:00 2001
From: Ekaterina Sokolova <e.sokolova@postgrespro.ru>
Date: Fri, 1 Apr 2022 21:36:21 -0500
Subject: [PATCH 2/2] Add extra statistics to explain for Nested Loop

For some distributions of data in tables, different loops in nested loop
joins can take different time and process different amounts of entries.
It makes average statistics returned by explain analyze not very useful for DBA.

This patch add collecting of min, max and total statistics for time and rows
across all loops to EXPLAIN ANALYSE. You need to set the VERBOSE flag to display
this information. The patch contains regression tests.

Example of results in TEXT format:
   ->  Append (actual rows=5 loops=5)
         Loop Min Rows: 2  Max Rows: 6  Total Rows: 23

Reviewed-by: Lukas Fittl, Justin Pryzby, Yugo Nagata, Julien Rouhaud.
---
 src/backend/commands/explain.c                |  42 ++++++-
 src/backend/executor/instrument.c             |  38 +++++-
 src/include/executor/instrument.h             |  10 ++
 src/test/regress/expected/explain.out         |  10 ++
 src/test/regress/expected/partition_prune.out | 117 ++++++++++++++++++
 src/test/regress/sql/partition_prune.sql      |  32 +++++
 6 files changed, 247 insertions(+), 2 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 06e089a1220..df14803ff06 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -119,7 +119,7 @@ static void show_instrumentation_count(const char *qlabel, int which,
 static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
 static void show_eval_params(Bitmapset *bms_params, ExplainState *es);
 static void show_loop_info(Instrumentation *instrument, bool isworker,
-		ExplainState *es);
+						   ExplainState *es);
 static const char *explain_get_index_name(Oid indexId);
 static void show_buffer_usage(ExplainState *es, const BufferUsage *usage,
 							  bool planning);
@@ -541,6 +541,9 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 	if (es->wal)
 		instrument_option |= INSTRUMENT_WAL;
 
+	if (es->verbose)
+		instrument_option |= INSTRUMENT_EXTRA;
+
 	/*
 	 * We always collect timing for the entire statement, even when node-level
 	 * timing is off, so we don't look at es->timing here.  (We could skip
@@ -1624,6 +1627,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			appendStringInfoString(es->str, " (never executed)");
 		else
 		{
+			/* without min and max values because actual result is 0 */
 			if (es->timing)
 			{
 				ExplainPropertyFloat("Actual Startup Time", "ms", 0.0, 3, es);
@@ -3989,6 +3993,11 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 	double		startup_ms = 1000.0 * instrument->startup / nloops;
 	double		total_ms = 1000.0 * instrument->total / nloops;
 	double		rows = instrument->ntuples / nloops;
+	double		loop_total_rows = instrument->ntuples;
+	double		loop_min_r = instrument->min_tuples;
+	double		loop_max_r = instrument->max_tuples;
+	double		loop_min_t_ms = 1000.0 * instrument->min_t;
+	double		loop_max_t_ms = 1000.0 * instrument->max_t;
 
 	if (es->format == EXPLAIN_FORMAT_TEXT)
 	{
@@ -4008,6 +4017,21 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 
 		if (!isworker)
 			appendStringInfoChar(es->str, ')');
+
+		if (nloops > 1 && es->verbose)
+		{
+			appendStringInfoChar(es->str, '\n');
+			ExplainIndentText(es);
+
+			if (es->timing)
+				appendStringInfo(es->str,
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f  Min Time: %.3f  Max Time: %.3f",
+								 loop_min_r, loop_max_r, loop_total_rows, loop_min_t_ms, loop_max_t_ms);
+			else
+				appendStringInfo(es->str,
+								 "Loop Min Rows: %.0f  Max Rows: %.0f  Total Rows: %.0f",
+								 loop_min_r, loop_max_r, loop_total_rows);
+		}
 	}
 	else
 	{
@@ -4017,8 +4041,24 @@ show_loop_info(Instrumentation *instrument, bool isworker, ExplainState *es)
 								 3, es);
 			ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
 								 3, es);
+			if (nloops > 1 && es->verbose)
+			{
+				ExplainPropertyFloat("Loop Min Time", "ms", loop_min_t_ms,
+									 3, es);
+				ExplainPropertyFloat("Loop Max Time", "ms", loop_max_t_ms,
+									 3, es);
+			}
 		}
+
 		ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);
+
+		if (nloops > 1 && es->verbose)
+		{
+			ExplainPropertyFloat("Loop Min Rows", NULL, loop_min_r, 0, es);
+			ExplainPropertyFloat("Loop Max Rows", NULL, loop_max_r, 0, es);
+			ExplainPropertyFloat("Loop Total Rows", NULL, loop_total_rows, 0, es);
+		}
+
 		ExplainPropertyFloat("Actual Loops", NULL, nloops, 0, es);
 	}
 }
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index c5ff02a8424..ac46011e516 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -34,11 +34,12 @@ InstrAlloc(int n, int instrument_options, bool async_mode)
 
 	/* initialize all fields to zeroes, then modify as needed */
 	instr = palloc0(n * sizeof(Instrumentation));
-	if (instrument_options & (INSTRUMENT_BUFFERS | INSTRUMENT_TIMER | INSTRUMENT_WAL))
+	if (instrument_options & (INSTRUMENT_BUFFERS | INSTRUMENT_TIMER | INSTRUMENT_WAL | INSTRUMENT_EXTRA))
 	{
 		bool		need_buffers = (instrument_options & INSTRUMENT_BUFFERS) != 0;
 		bool		need_wal = (instrument_options & INSTRUMENT_WAL) != 0;
 		bool		need_timer = (instrument_options & INSTRUMENT_TIMER) != 0;
+		bool		need_extra = (instrument_options & INSTRUMENT_EXTRA) != 0;
 		int			i;
 
 		for (i = 0; i < n; i++)
@@ -46,6 +47,7 @@ InstrAlloc(int n, int instrument_options, bool async_mode)
 			instr[i].need_bufusage = need_buffers;
 			instr[i].need_walusage = need_wal;
 			instr[i].need_timer = need_timer;
+			instr[i].need_extra = need_extra;
 			instr[i].async_mode = async_mode;
 		}
 	}
@@ -61,6 +63,7 @@ InstrInit(Instrumentation *instr, int instrument_options)
 	instr->need_bufusage = (instrument_options & INSTRUMENT_BUFFERS) != 0;
 	instr->need_walusage = (instrument_options & INSTRUMENT_WAL) != 0;
 	instr->need_timer = (instrument_options & INSTRUMENT_TIMER) != 0;
+	instr->need_extra = (instrument_options & INSTRUMENT_EXTRA) != 0;
 }
 
 /* Entry to a plan node */
@@ -154,6 +157,35 @@ InstrEndLoop(Instrumentation *instr)
 	instr->startup += instr->firsttuple;
 	instr->total += totaltime;
 	instr->ntuples += instr->tuplecount;
+
+	/*
+	 * this is first loop
+	 *
+	 * We only initialize the min values. We don't need to bother with the
+	 * max, because those are 0 and the non-zero values will get updated a
+	 * couple lines later.
+	 */
+	if (instr->need_extra)
+	{
+		if (instr->nloops == 0)
+		{
+			instr->min_t = totaltime;
+			instr->min_tuples = instr->tuplecount;
+		}
+
+		if (instr->min_t > totaltime)
+			instr->min_t = totaltime;
+
+		if (instr->max_t < totaltime)
+			instr->max_t = totaltime;
+
+		if (instr->min_tuples > instr->tuplecount)
+			instr->min_tuples = instr->tuplecount;
+
+		if (instr->max_tuples < instr->tuplecount)
+			instr->max_tuples = instr->tuplecount;
+	}
+
 	instr->nloops += 1;
 
 	/* Reset for next cycle (if any) */
@@ -186,6 +218,10 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
 	dst->nloops += add->nloops;
 	dst->nfiltered1 += add->nfiltered1;
 	dst->nfiltered2 += add->nfiltered2;
+	dst->min_t = Min(dst->min_t, add->min_t);
+	dst->max_t = Max(dst->max_t, add->max_t);
+	dst->min_tuples = Min(dst->min_tuples, add->min_tuples);
+	dst->max_tuples = Max(dst->max_tuples, add->max_tuples);
 
 	/* Add delta of buffer usage since entry to node's totals */
 	if (dst->need_bufusage)
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 1b7157bdd15..e6178e248dc 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -58,6 +58,8 @@ typedef enum InstrumentOption
 	INSTRUMENT_BUFFERS = 1 << 1,	/* needs buffer usage */
 	INSTRUMENT_ROWS = 1 << 2,	/* needs row count */
 	INSTRUMENT_WAL = 1 << 3,	/* needs WAL usage */
+	INSTRUMENT_EXTRA = 1 << 4,	/* needs counters for min,
+								 * max and total values */
 	INSTRUMENT_ALL = PG_INT32_MAX
 } InstrumentOption;
 
@@ -67,6 +69,8 @@ typedef struct Instrumentation
 	bool		need_timer;		/* true if we need timer data */
 	bool		need_bufusage;	/* true if we need buffer usage data */
 	bool		need_walusage;	/* true if we need WAL usage data */
+	bool		need_extra;		/* true if we need min, max and total
+								 * statistics for loops */
 	bool		async_mode;		/* true if node is in async mode */
 	/* Info about current plan cycle: */
 	bool		running;		/* true if we've completed first tuple */
@@ -79,7 +83,13 @@ typedef struct Instrumentation
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* total startup time (in seconds) */
 	double		total;			/* total time (in seconds) */
+	double		min_t;			/* time of fastest loop (in seconds) */
+	double		max_t;			/* time of slowest loop (in seconds) */
 	double		ntuples;		/* total tuples produced */
+	double		min_tuples;		/* min counter of produced tuples for all
+								 * loops */
+	double		max_tuples;		/* max counter of produced tuples for all
+								 * loops */
 	double		ntuples2;		/* secondary node-specific tuple counter */
 	double		nloops;			/* # of run cycles for this node */
 	double		nfiltered1;		/* # of tuples removed by scanqual or joinqual */
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index bc361759219..c70d0e288da 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -357,8 +357,13 @@ select jsonb_pretty(
                              "Actual Loops": 0,             +
                              "Startup Cost": 0.0,           +
                              "Async Capable": false,        +
+                             "Loop Max Rows": 0,            +
+                             "Loop Max Time": 0.0,          +
+                             "Loop Min Rows": 0,            +
+                             "Loop Min Time": 0.0,          +
                              "Relation Name": "tenk1",      +
                              "Parallel Aware": true,        +
+                             "Loop Total Rows": 0,          +
                              "Local Hit Blocks": 0,         +
                              "Temp Read Blocks": 0,         +
                              "Actual Total Time": 0.0,      +
@@ -403,7 +408,12 @@ select jsonb_pretty(
                      "Actual Loops": 0,                     +
                      "Startup Cost": 0.0,                   +
                      "Async Capable": false,                +
+                     "Loop Max Rows": 0,                    +
+                     "Loop Max Time": 0.0,                  +
+                     "Loop Min Rows": 0,                    +
+                     "Loop Min Time": 0.0,                  +
                      "Parallel Aware": false,               +
+                     "Loop Total Rows": 0,                  +
                      "Sort Space Used": 0,                  +
                      "Local Hit Blocks": 0,                 +
                      "Temp Read Blocks": 0,                 +
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c779..18617b9e206 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1962,6 +1962,24 @@ begin
     end loop;
 end;
 $$;
+create function explain_verbose_parallel_append(text) returns setof text
+language plpgsql as
+$$
+declare
+    ln text;
+begin
+    for ln in
+        execute format('explain (analyze, verbose, costs off, summary off, timing off) %s',
+            $1)
+    loop
+        ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
+        ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop Min Rows: \d+  Max Rows: \d+  Total Rows: \d+',
+                                 'Loop Min Rows: N  Max Rows: N  Total Rows: N');
+        return next ln;
+    end loop;
+end;
+$$;
 prepare ab_q4 (int, int) as
 select avg(a) from ab where a between $1 and $2 and b < 4;
 -- Encourage use of parallel plans
@@ -2218,6 +2236,39 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
 (28 rows)
 
+-- Tests for extra statistics
+create table lprt_b (b int not null);
+insert into lprt_b select generate_series(1,20);
+select explain_verbose_parallel_append('select * from lprt_a join lprt_b on a != b');
+                       explain_verbose_parallel_append                        
+------------------------------------------------------------------------------
+ Nested Loop (actual rows=N loops=N)
+   Output: lprt_a.a, lprt_b.b
+   Join Filter: (lprt_a.a <> lprt_b.b)
+   Rows Removed by Join Filter: 4
+   ->  Gather (actual rows=N loops=N)
+         Output: lprt_b.b
+         Workers Planned: 2
+         Workers Launched: N
+         ->  Parallel Seq Scan on public.lprt_b (actual rows=N loops=N)
+               Loop Min Rows: N  Max Rows: N  Total Rows: N
+               Output: lprt_b.b
+               Worker 0:  actual rows=N loops=N
+               Worker 1:  actual rows=N loops=N
+   ->  Materialize (actual rows=N loops=N)
+         Loop Min Rows: N  Max Rows: N  Total Rows: N
+         Output: lprt_a.a
+         ->  Gather (actual rows=N loops=N)
+               Output: lprt_a.a
+               Workers Planned: 1
+               Workers Launched: N
+               ->  Parallel Seq Scan on public.lprt_a (actual rows=N loops=N)
+                     Loop Min Rows: N  Max Rows: N  Total Rows: N
+                     Output: lprt_a.a
+                     Worker 0:  actual rows=N loops=N
+(24 rows)
+
+drop table lprt_b;
 delete from lprt_a where a = 1;
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
                                      explain_parallel_append                                     
@@ -2715,6 +2766,72 @@ order by tbl1.col1, tprt.col1;
  1001 | 1001
 (3 rows)
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=23 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=5 loops=5)
+         Loop Min Rows: 2  Max Rows: 6  Total Rows: 23
+         ->  Index Scan using tprt1_idx on public.tprt_1 (actual rows=2 loops=5)
+               Loop Min Rows: 2  Max Rows: 2  Total Rows: 10
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 < tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=3 loops=4)
+               Loop Min Rows: 2  Max Rows: 3  Total Rows: 11
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 < tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=1 loops=2)
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 < tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 < tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 < tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 < tbl1.col1)
+(27 rows)
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+                                   QUERY PLAN                                    
+---------------------------------------------------------------------------------
+ Nested Loop (actual rows=3 loops=1)
+   Output: tbl1.col1, tprt.col1
+   ->  Seq Scan on public.tbl1 (actual rows=5 loops=1)
+         Output: tbl1.col1
+   ->  Append (actual rows=1 loops=5)
+         Loop Min Rows: 0  Max Rows: 1  Total Rows: 3
+         ->  Index Scan using tprt1_idx on public.tprt_1 (never executed)
+               Output: tprt_1.col1
+               Index Cond: (tprt_1.col1 = tbl1.col1)
+         ->  Index Scan using tprt2_idx on public.tprt_2 (actual rows=1 loops=2)
+               Loop Min Rows: 1  Max Rows: 1  Total Rows: 2
+               Output: tprt_2.col1
+               Index Cond: (tprt_2.col1 = tbl1.col1)
+         ->  Index Scan using tprt3_idx on public.tprt_3 (actual rows=0 loops=3)
+               Loop Min Rows: 0  Max Rows: 1  Total Rows: 1
+               Output: tprt_3.col1
+               Index Cond: (tprt_3.col1 = tbl1.col1)
+         ->  Index Scan using tprt4_idx on public.tprt_4 (never executed)
+               Output: tprt_4.col1
+               Index Cond: (tprt_4.col1 = tbl1.col1)
+         ->  Index Scan using tprt5_idx on public.tprt_5 (never executed)
+               Output: tprt_5.col1
+               Index Cond: (tprt_5.col1 = tbl1.col1)
+         ->  Index Scan using tprt6_idx on public.tprt_6 (never executed)
+               Output: tprt_6.col1
+               Index Cond: (tprt_6.col1 = tbl1.col1)
+(26 rows)
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index d70bd8610cb..68110e20eeb 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -469,6 +469,25 @@ begin
 end;
 $$;
 
+create function explain_verbose_parallel_append(text) returns setof text
+language plpgsql as
+$$
+declare
+    ln text;
+begin
+    for ln in
+        execute format('explain (analyze, verbose, costs off, summary off, timing off) %s',
+            $1)
+    loop
+        ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
+        ln := regexp_replace(ln, 'actual rows=\d+ loops=\d+', 'actual rows=N loops=N');
+        ln := regexp_replace(ln, 'Loop Min Rows: \d+  Max Rows: \d+  Total Rows: \d+',
+                                 'Loop Min Rows: N  Max Rows: N  Total Rows: N');
+        return next ln;
+    end loop;
+end;
+$$;
+
 prepare ab_q4 (int, int) as
 select avg(a) from ab where a between $1 and $2 and b < 4;
 
@@ -528,6 +547,12 @@ insert into lprt_a values(3),(3);
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 3)');
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
 
+-- Tests for extra statistics
+create table lprt_b (b int not null);
+insert into lprt_b select generate_series(1,20);
+select explain_verbose_parallel_append('select * from lprt_a join lprt_b on a != b');
+drop table lprt_b;
+
 delete from lprt_a where a = 1;
 
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
@@ -654,6 +679,13 @@ select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
 order by tbl1.col1, tprt.col1;
 
+-- Tests for extra statistics
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
+
+explain (analyze, verbose, costs off, summary off, timing off)
+select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
+
 -- Last partition
 delete from tbl1;
 insert into tbl1 values (4400);
-- 
2.17.1