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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-03-24 15:53:06 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-03-24 15:53:06 -0400 |
| commit | 054723bcc5b03e40d6341b26b2dce5222a66ce4c (patch) | |
| tree | a3dbf9364326f4d9a609e96f3a17a54ff4cd840d /src/backend/executor/execMain.c | |
| parent | 9288645b596efde3a58e267896b38f8f089a2920 (diff) | |
| download | postgresql-054723bcc5b03e40d6341b26b2dce5222a66ce4c.tar.gz postgresql-054723bcc5b03e40d6341b26b2dce5222a66ce4c.zip | |
Fix ExecOpenScanRelation to take a lock on a ROW_MARK_COPY relation.
ExecOpenScanRelation assumed that any relation listed in the ExecRowMark
list has been locked by InitPlan; but this is not true if the rel's
markType is ROW_MARK_COPY, which is possible if it's a foreign table.
In most (possibly all) cases, failure to acquire a lock here isn't really
problematic because the parser, planner, or plancache would have taken the
appropriate lock already. In principle though it might leave us vulnerable
to working with a relation that we hold no lock on, and in any case if the
executor isn't depending on previously-taken locks otherwise then it should
not do so for ROW_MARK_COPY relations.
Noted by Etsuro Fujita. Back-patch to all active versions, since the
inconsistency has been there a long time. (It's almost certainly
irrelevant in 9.0, since that predates foreign tables, but the code's
still wrong on its own terms.)
Diffstat (limited to 'src/backend/executor/execMain.c')
| -rw-r--r-- | src/backend/executor/execMain.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index d46cdf8c349..614b00bd24f 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -820,6 +820,10 @@ InitPlan(QueryDesc *queryDesc, int eflags) if (rc->isParent) continue; + /* + * If you change the conditions under which rel locks are acquired + * here, be sure to adjust ExecOpenScanRelation to match. + */ switch (rc->markType) { case ROW_MARK_EXCLUSIVE: |