On Mon, Apr 18, 2016 at 05:48:17PM +0300, Teodor Sigaev wrote: > >>Added, see attached patch (based on v3.1) > > > >With this applied, I am getting a couple errors I have not seen before > >after extensive crash recovery testing: > >ERROR: attempted to delete invisible tuple > >ERROR: unexpected chunk number 1 (expected 2) for toast value > >100338365 in pg_toast_16425 > Huh, seems, it's not related to GIN at all... Indexes don't play with toast > machinery. The single place where this error can occur is a heap_delete() - > deleting already deleted tuple.
Like you, I would not expect gin_alone_cleanup-4.patch to cause such an error. I get the impression Jeff has a test case that he had run in many iterations against the unpatched baseline. I also get the impression that a similar or smaller number of its iterations against gin_alone_cleanup-4.patch triggered these two errors (once apiece, or multiple times?). Jeff, is that right? If so, until we determine the cause, we should assume the cause arrived in gin_alone_cleanup-4.patch. An error in pointer arithmetic or locking might corrupt an unrelated buffer, leading to this symptom. > >I've restarted the test harness with intentional crashes turned off, > >to see if the problems are related to crash recovery or are more > >generic than that. > > > >I've never seen these particular problems before, so don't have much > >insight into what might be going on or how to debug it. Could you describe the test case in sufficient detail for Teodor to reproduce your results? > Check my reasoning: In version 4 I added a remebering of tail of pending > list into blknoFinish variable. And when we read page which was a tail on > cleanup start then we sets cleanupFinish variable and after cleaning that > page we will stop further cleanup. Any insert caused during cleanup will be > placed after blknoFinish (corner case: in that page), so, vacuum should not > miss tuples marked as deleted. Would any hacker volunteer to review Teodor's reasoning here? Thanks, nm -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
