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Consider disk-based hash aggregation to implement DISTINCT.

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Correct oversight in 1f39bce0. If enable_hashagg_disk=true, we should
consider hash aggregation for DISTINCT when applicable.
This commit is contained in:
Jeff Davis 2020-03-24 18:19:51 -07:00
parent 3649133b14
commit dd8e19132a
1 changed files with 2 additions and 2 deletions
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4
src/backend/optimizer/plan/planner.c
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@ -4868,8 +4868,8 @@ create_distinct_paths(PlannerInfo *root,
Size hashentrysize = hash_agg_entry_size( Size hashentrysize = hash_agg_entry_size(
0, cheapest_input_path->pathtarget->width, 0); 0, cheapest_input_path->pathtarget->width, 0);
/* Allow hashing only if hashtable is predicted to fit in work_mem */ allow_hash = enable_hashagg_disk ||
allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L); (hashentrysize * numDistinctRows <= work_mem * 1024L);
} }
if (allow_hash && grouping_is_hashable(parse->distinctClause)) if (allow_hash && grouping_is_hashable(parse->distinctClause))