postgres.git / summary / log / commit / refs

commit    2cccb627f10d5dd4c21806fa251e4fb61eadd28c
Author:   Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date:     Wed Nov 18 10:39:15 2020 +0000

    Skip allocating hash table in EXPLAIN-only mode.
    
    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 d87677d6599..5bf9e99bbc8 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: dfab7f2f9481]