From 5d0afe5d92649f575d9b09ae19b31d2bfd5bfd12 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 1 Jan 2020 13:09:33 -0600
Subject: [PATCH v1 1/2] refactor: show_hinstrument and avoid showing memory
 use if not verbose..

This changes explain analyze at least for Hash(join), but doesn't break
affect regression tests, since they all run explain without analyze, so
nbatch=0, and no stats are shown.

But for future patch to show stats for HashAgg (for which nbatch=1, always), we
want to show buckets in explain analyze, but don't want to show memory, which
is machine-specific.
---
 src/backend/commands/explain.c | 73 ++++++++++++++++++++++++++----------------
 1 file changed, 45 insertions(+), 28 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 497a3bd..d5eaf15 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -101,6 +101,7 @@ static void show_sortorder_options(StringInfo buf, Node *sortexpr,
 static void show_tablesample(TableSampleClause *tsc, PlanState *planstate,
 							 List *ancestors, ExplainState *es);
 static void show_sort_info(SortState *sortstate, ExplainState *es);
+static void show_hinstrument(ExplainState *es, HashInstrumentation *h);
 static void show_hash_info(HashState *hashstate, ExplainState *es);
 static void show_tidbitmap_info(BitmapHeapScanState *planstate,
 								ExplainState *es);
@@ -2702,43 +2703,59 @@ show_hash_info(HashState *hashstate, ExplainState *es)
 		}
 	}
 
-	if (hinstrument.nbatch > 0)
-	{
-		long		spacePeakKb = (hinstrument.space_peak + 1023) / 1024;
+	show_hinstrument(es, &hinstrument);
+}
 
-		if (es->format != EXPLAIN_FORMAT_TEXT)
-		{
-			ExplainPropertyInteger("Hash Buckets", NULL,
-								   hinstrument.nbuckets, es);
-			ExplainPropertyInteger("Original Hash Buckets", NULL,
-								   hinstrument.nbuckets_original, es);
-			ExplainPropertyInteger("Hash Batches", NULL,
-								   hinstrument.nbatch, es);
-			ExplainPropertyInteger("Original Hash Batches", NULL,
-								   hinstrument.nbatch_original, es);
-			ExplainPropertyInteger("Peak Memory Usage", "kB",
-								   spacePeakKb, es);
-		}
-		else if (hinstrument.nbatch_original != hinstrument.nbatch ||
-				 hinstrument.nbuckets_original != hinstrument.nbuckets)
-		{
+/*
+ * Show hash bucket stats and (optionally) memory.
+ */
+static void
+show_hinstrument(ExplainState *es, HashInstrumentation *h)
+{
+	long		spacePeakKb = (h->space_peak + 1023) / 1024;
+
+	if (h->nbatch <= 0)
+		return;
+
+	if (es->format != EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainPropertyInteger("Hash Buckets", NULL,
+							   h->nbuckets, es);
+		ExplainPropertyInteger("Original Hash Buckets", NULL,
+							   h->nbuckets_original, es);
+		ExplainPropertyInteger("Hash Batches", NULL,
+							   h->nbatch, es);
+		ExplainPropertyInteger("Original Hash Batches", NULL,
+							   h->nbatch_original, es);
+		ExplainPropertyInteger("Peak Memory Usage", "kB",
+							   spacePeakKb, es);
+	}
+	else
+	{
+		if (h->nbatch_original != h->nbatch ||
+			 h->nbuckets_original != h->nbuckets) {
 			appendStringInfoSpaces(es->str, es->indent * 2);
 			appendStringInfo(es->str,
-							 "Buckets: %d (originally %d)  Batches: %d (originally %d)  Memory Usage: %ldkB\n",
-							 hinstrument.nbuckets,
-							 hinstrument.nbuckets_original,
-							 hinstrument.nbatch,
-							 hinstrument.nbatch_original,
-							 spacePeakKb);
+						"Buckets: %d (originally %d)   Batches: %d (originally %d)",
+						h->nbuckets,
+						h->nbuckets_original,
+						h->nbatch,
+						h->nbatch_original);
 		}
 		else
 		{
 			appendStringInfoSpaces(es->str, es->indent * 2);
 			appendStringInfo(es->str,
-							 "Buckets: %d  Batches: %d  Memory Usage: %ldkB\n",
-							 hinstrument.nbuckets, hinstrument.nbatch,
-							 spacePeakKb);
+						"Buckets: %d  Batches: %d",
+						h->nbuckets,
+						h->nbatch);
 		}
+
+		if (es->verbose && es->analyze)
+			appendStringInfo(es->str,
+					"  Memory Usage: %ldkB",
+					spacePeakKb);
+		appendStringInfoChar(es->str, '\n');
 	}
 }
 
-- 
2.7.4