From b12fd41c695b43c76b0a9a4d19ba43b05536440c Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 9 Jun 2016 12:40:23 -0400 Subject: Don't generate parallel paths for rels with parallel-restricted outputs. Such paths are unsafe. To make it cheaper to detect when this case applies, track whether a relation's default PathTarget contains any non-Vars. In most cases, the answer will be no, which enables us to determine cheaply that the target list for a proposed path is parallel-safe. However, subquery pull-up can create cases that require us to inspect the target list more carefully. Amit Kapila, reviewed by me. --- src/backend/optimizer/util/placeholder.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'src/backend/optimizer/util/placeholder.c') diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c index b210914b853..5b85a4ddadc 100644 --- a/src/backend/optimizer/util/placeholder.c +++ b/src/backend/optimizer/util/placeholder.c @@ -393,6 +393,7 @@ add_placeholders_to_base_rels(PlannerInfo *root) rel->reltarget->exprs = lappend(rel->reltarget->exprs, copyObject(phinfo->ph_var)); + rel->reltarget_has_non_vars = true; /* reltarget's cost and width fields will be updated later */ } } @@ -427,6 +428,7 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel, /* Yup, add it to the output */ joinrel->reltarget->exprs = lappend(joinrel->reltarget->exprs, phinfo->ph_var); + joinrel->reltarget_has_non_vars = true; joinrel->reltarget->width += phinfo->ph_width; /* -- cgit v1.2.3