On 2013-08-30 17:23:51 -0400, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > No need, found the bug. And I think can build a testcase myself. > > > ExecReScanMergeAppend resets ms_initialized, but doesn't clear the > > binaryheap. Thus no new elements fit. > > Sounds like a bug all right, but I'm not convinced it explains Terje's > report. The thing this theory doesn't explain is why would Terje be > having trouble reproducing the failure? Seems like re-running the same > query ought to produce the same failure.
The number of rescans can be rather data-dependant, so I'd guess that's the reason. If many of the subplans don't return a tuple, it can take several resets to actually ever reach the heap's limit as we don't add the subplan to the heap in that case. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs