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| author | Peter Eisentraut <peter_e@gmx.net> | 2018-03-06 21:54:37 -0500 |
|---|---|---|
| committer | Peter Eisentraut <peter_e@gmx.net> | 2018-03-06 21:54:37 -0500 |
| commit | 5b804cc168a52039be02f392780b9e8c8db74412 (patch) | |
| tree | 0bcfeb59b00f16afa2b7affc64effe0998956d28 | |
| parent | a3739e376fbc9d6e332ce33d42426b1d8b59f20b (diff) | |
| download | postgresql-5b804cc168a52039be02f392780b9e8c8db74412.tar.gz postgresql-5b804cc168a52039be02f392780b9e8c8db74412.zip | |
Fix costing of parallel hash joins.
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
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 2 | ||||
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 2 |
2 files changed, 3 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index d8db0b29e1f..36b3dfabb80 100644 --- 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 */ void initial_cost_hashjoin(PlannerInfo *root, JoinCostWorkspace *workspace, diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 688f440b92e..3fd3cc7670b 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -814,7 +814,7 @@ try_partial_hashjoin_path(PlannerInfo *root, * cost. Bail out right away if it looks terrible. */ initial_cost_hashjoin(root, &workspace, jointype, hashclauses, - outer_path, inner_path, extra, true); + outer_path, inner_path, extra, parallel_hash); if (!add_partial_path_precheck(joinrel, workspace.total_cost, NIL)) return; |