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author Peter Eisentraut <peter_e@gmx.net>

Wed, 7 Mar 2018 02:54:37 +0000 (21:54 -0500)

committer Peter Eisentraut <peter_e@gmx.net>

Wed, 7 Mar 2018 02:54:37 +0000 (21:54 -0500)

Commit 1804284042e659e7d16904e7bbb0ad546394b6a3 established that single-batch
parallel-aware hash joins could create one large shared hash table using the
combined work_mem budget of all participants. The costing accidentally
assumed that parallel-oblivious hash joins could also do that. The
documentation for initial_cost_hashjoin() also failed to mention the new
argument. Repair.

Author: Thomas Munro
Reported-By: Antonin Houska
Reviewed-By: Antonin Houska
Discussion: https://postgr.es/m/12441.1513935950%40localhost

src/backend/optimizer/path/costsize.c patch | blob | blame | history

src/backend/optimizer/path/joinpath.c patch | blob | blame | history

diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c

index d8db0b29e1f97394bd6ef4a0de4ad3eb1ea2e2e4..36b3dfabb80b944cd18f64f5c41a62c68ea9fda9 100644 (file)

--- a/src/backend/optimizer/path/costsize.c

+++ b/src/backend/optimizer/path/costsize.c

@@ -3143,6 +3143,8 @@ cached_scansel(PlannerInfo *root, RestrictInfo *rinfo, PathKey *pathkey)

* 'outer_path' is the outer input to the join

* 'inner_path' is the inner input to the join

* 'extra' contains miscellaneous information about the join

+ * 'parallel_hash' indicates that inner_path is partial and that a shared

+ * hash table will be built in parallel