database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Rework HashAgg GUCs.

Browse Source 
Eliminate enable_groupingsets_hash_disk, which was primarily useful
for testing grouping sets that use HashAgg and spill. Instead, hack
the table stats to convince the planner to choose hashed aggregation
for grouping sets that will spill to disk. Suggested by Melanie
Plageman.

Rename enable_hashagg_disk to hashagg_avoid_disk_plan, and invert the
meaning of on/off. The new name indicates more strongly that it only
affects the planner. Also, the word "avoid" is less definite, which
should avoid surprises when HashAgg still needs to use the
disk. Change suggested by Justin Pryzby, though I chose a different
GUC name.

Discussion: https://postgr.es/m/CAAKRu_aisiENMsPM2gC4oUY1hHG3yrCwY-fXUg22C6_MJUwQdA%40mail.gmail.com
Discussion: https://postgr.es/m/20200610021544.GA14879@telsasoft.com
Backpatch-through: 13
This commit is contained in:
Jeff Davis
2020-06-11 11:58:16 -07:00
parent 5940ffb221
commit 92c58fd948
10 changed files with 119 additions and 158 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/utils/misc/guc.c
View File

@ -1002,22 +1002,12 @@ static struct config_bool ConfigureNamesBool[] =
NULL, NULL, NULL
},
{
{"enable_hashagg_disk", PGC_USERSET, QUERY_TUNING_METHOD,
gettext_noop("Enables the planner's use of hashed aggregation plans that are expected to exceed work_mem."),
{"hashagg_avoid_disk_plan", PGC_USERSET, QUERY_TUNING_METHOD,
gettext_noop("Causes the planner to avoid hashed aggregation plans that are expected to use the disk."),
NULL,
GUC_EXPLAIN
},
&enable_hashagg_disk,
true,
NULL, NULL, NULL
},
{
{"enable_groupingsets_hash_disk", PGC_USERSET, QUERY_TUNING_METHOD,
gettext_noop("Enables the planner's use of hashed aggregation plans for groupingsets when the total size of the hash tables is expected to exceed work_mem."),
NULL,
GUC_EXPLAIN
},
&enable_groupingsets_hash_disk,
&hashagg_avoid_disk_plan,
false,
NULL, NULL, NULL
},