database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-19 13:42:17 +03:00
Code Activity

Reduce memory used by partitionwise joins

Browse Source 
Specifically, this commit reduces the memory consumed by the
SpecialJoinInfos that are allocated for child joins in
try_partitionwise_join() by freeing them at the end of creating paths
for each child join.

A SpecialJoinInfo allocated for a given child join is a copy of the
parent join's SpecialJoinInfo, which contains the translated copies
of the various Relids bitmapsets and semi_rhs_exprs, which is a List
of Nodes.  The newly added freeing step frees the struct itself and
the various bitmapsets, but not semi_rhs_exprs, because there's no
handy function to free the memory of Node trees.

Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Reviewed-by: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://postgr.es/m/CAExHW5tHqEf3ASVqvFFcghYGPfpy7o3xnvhHwBGbJFMRH8KjNw@mail.gmail.com
This commit is contained in:
Amit Langote
2024-03-25 12:02:40 +09:00
parent 619bc23a1a
commit 5278d0a2e8
3 changed files with 42 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/backend/optimizer/path/joinrels.c
View File

@@ -45,6 +45,7 @@ static void try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1,
static SpecialJoinInfo *build_child_join_sjinfo(PlannerInfo *root,
SpecialJoinInfo *parent_sjinfo,
Relids left_relids, Relids right_relids);
static void free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo);
static void compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
RelOptInfo *rel2, RelOptInfo *joinrel,
SpecialJoinInfo *parent_sjinfo,
@@ -1659,6 +1660,7 @@ try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
child_restrictlist);
pfree(appinfos);
free_child_join_sjinfo(child_sjinfo);
}
}
@@ -1666,6 +1668,9 @@ try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
* Construct the SpecialJoinInfo for a child-join by translating
* SpecialJoinInfo for the join between parents. left_relids and right_relids
* are the relids of left and right side of the join respectively.
*
* If translations are added to or removed from this function, consider
* updating free_child_join_sjinfo() accordingly.
*/
static SpecialJoinInfo *
build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
@@ -1705,6 +1710,37 @@ build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
return sjinfo;
}
/*
* free_child_join_sjinfo
* Free memory consumed by a SpecialJoinInfo created by
* build_child_join_sjinfo()
*
* Only members that are translated copies of their counterpart in the parent
* SpecialJoinInfo are freed here.
*/
static void
free_child_join_sjinfo(SpecialJoinInfo *sjinfo)
{
/*
* Dummy SpecialJoinInfos of inner joins do not have any translated fields
* and hence no fields that to be freed.
*/
if (sjinfo->jointype != JOIN_INNER)
{
bms_free(sjinfo->min_lefthand);
bms_free(sjinfo->min_righthand);
bms_free(sjinfo->syn_lefthand);
bms_free(sjinfo->syn_righthand);
/*
* semi_rhs_exprs may in principle be freed, but a simple pfree() does
* not suffice, so we leave it alone.
*/
}
pfree(sjinfo);
}
/*
* compute_partition_bounds
* Compute the partition bounds for a join rel from those for inputs