From 08a823e53b78507c9fcc8a6d77de1a1d5b7c1b13 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 24 Aug 2016 14:37:51 -0400 Subject: Fix improper repetition of previous results from a hashed aggregate. ExecReScanAgg's check for whether it could re-use a previously calculated hashtable neglected the possibility that the Agg node might reference PARAM_EXEC Params that are not referenced by its input plan node. That's okay if the Params are in upper tlist or qual expressions; but if one appears in aggregate input expressions, then the hashtable contents need to be recomputed when the Param's value changes. To avoid unnecessary performance degradation in the case of a Param that isn't within an aggregate input, add logic to the planner to determine which Params are within aggregate inputs. This requires a new field in struct Agg, but fortunately we never write plans to disk, so this isn't an initdb-forcing change. Per report from Jeevan Chalke. This has been broken since forever, so back-patch to all supported branches. Andrew Gierth, with minor adjustments by me Report: --- src/backend/optimizer/plan/createplan.c | 1 + 1 file changed, 1 insertion(+) (limited to 'src/backend/optimizer/plan/createplan.c') diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 9cf133d8a16..addb030b6b5 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -4299,6 +4299,7 @@ make_agg(PlannerInfo *root, List *tlist, List *qual, node->grpColIdx = grpColIdx; node->grpOperators = grpOperators; node->numGroups = numGroups; + node->aggParams = NULL; /* SS_finalize_plan() will fill this */ copy_plan_costsize(plan, lefttree); /* only care about copying size */ cost_agg(&agg_path, root, -- cgit v1.2.3