From dd8e19132acfbb28d579288a412ed6c0a5ea338b Mon Sep 17 00:00:00 2001 From: Jeff Davis Date: Tue, 24 Mar 2020 18:19:51 -0700 Subject: [PATCH] Consider disk-based hash aggregation to implement DISTINCT. Correct oversight in 1f39bce0. If enable_hashagg_disk=true, we should consider hash aggregation for DISTINCT when applicable. --- src/backend/optimizer/plan/planner.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 5da0528382..b65abf6046 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -4868,8 +4868,8 @@ create_distinct_paths(PlannerInfo *root, Size hashentrysize = hash_agg_entry_size( 0, cheapest_input_path->pathtarget->width, 0); - /* Allow hashing only if hashtable is predicted to fit in work_mem */ - allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L); + allow_hash = enable_hashagg_disk || + (hashentrysize * numDistinctRows <= work_mem * 1024L); } if (allow_hash && grouping_is_hashable(parse->distinctClause))