postgres.git / summary / log / commit / refs

commit    340ae3cfb8f38a49664c0da3ff033346e92f0450
Author:   Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date:     Fri Nov 20 12:41:14 2020 +0000
First released in: 14.0, 9.5.25, 9.6.21, 10.16, 11.11, 12.6, 13.2

    Skip allocating hash table in EXPLAIN-only mode.
    
    This is a backpatch of commit 2cccb627f1, backpatched due to popular
    demand. Backpatch to all supported versions.
    
    Author: Alexey Bashtanov
    Discussion: https://www.postgresql.org/message-id/36823f65-050d-ae24-aa4d-a37726998240%40imap.cc


 src/backend/executor/nodeAgg.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 75e5bbf209d..8a0bd887bf0 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -3665,7 +3665,11 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 							&aggstate->hash_ngroups_limit,
 							&aggstate->hash_planned_partitions);
 		find_hash_columns(aggstate);
-		build_hash_tables(aggstate);
+
+		/* Skip massive memory allocation if we are just doing EXPLAIN */
+		if (!(eflags & EXEC_FLAG_EXPLAIN_ONLY))
+			build_hash_tables(aggstate);
+
 		aggstate->table_filled = false;
 
 		/* Initialize this to 1, meaning nothing spilled, yet */


[parent: 9e9a31bd0096]