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Revert "Fix parallel-safety check of expressions and predicate for index builds"

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This reverts commit eae7be600b, following a discussion with Tom Lane,
due to concerns that this impacts the decisions made by the planner for
the number of workers spawned based on the inlining and const-folding of
index expressions and predicate for cases that would have worked until
this commit.

Discussion: https://postgr.es/m/162802.1709746091@sss.pgh.pa.us
Backpatch-through: 12
This commit is contained in:
Michael Paquier
2024-03-07 08:31:00 +09:00
parent 1b3029be5d
commit c46817ee51
5 changed files with 2 additions and 121 deletions
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12
src/backend/optimizer/plan/planner.c
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@@ -6695,18 +6695,10 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
* Currently, parallel workers can't access the leader's temporary tables.
* Furthermore, any index predicate or index expressions must be parallel
* safe.
*
* Fetch the list of expressions and predicates directly from the
* catalogs. Retrieving this information from the relcache would cause
* the expressions and predicates to be flattened, losing properties that
* can be important to check if parallel workers can be used. For
* example, immutable parallel-unsafe functions, that cannot be used in
* parallel workers, would be changed to Const nodes, that are safe in
* parallel workers.
*/
if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
!is_parallel_safe(root, (Node *) get_index_expressions(indexOid)) ||
!is_parallel_safe(root, (Node *) get_index_predicate(indexOid)))
!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
{
parallel_workers = 0;
goto done;