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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-03-11 23:18:03 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-03-11 23:18:03 -0400 |
| commit | f4abd0241de20d5d6a79b84992b9e88603d44134 (patch) | |
| tree | 7b43a57a988932798cebdf16375f4aab860c52c0 /src/backend/optimizer/plan/planner.c | |
| parent | b746d0c32d4fe749c8d39ccb09d8f0fb38bcc197 (diff) | |
| download | postgresql-f4abd0241de20d5d6a79b84992b9e88603d44134.tar.gz postgresql-f4abd0241de20d5d6a79b84992b9e88603d44134.zip | |
Support flattening of empty-FROM subqueries and one-row VALUES tables.
We can't handle this in the general case due to limitations of the
planner's data representations; but we can allow it in many useful cases,
by being careful to flatten only when we are pulling a single-row subquery
up into a FROM (or, equivalently, inner JOIN) node that will still have at
least one remaining relation child. Per discussion of an example from
Kyotaro Horiguchi.
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index b02a1079ae4..88b91f1b205 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -352,8 +352,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse, * Check to see if any subqueries in the jointree can be merged into this * query. */ - parse->jointree = (FromExpr *) - pull_up_subqueries(root, (Node *) parse->jointree); + pull_up_subqueries(root); /* * If this is a simple UNION ALL query, flatten it into an appendrel. We |