Hi Michael, On Mon, Nov 6, 2017 at 6:18 PM, Michael Paquier <michael.paqu...@gmail.com> wrote: > Did you really test WAL replay?
Is there a way to test this other than installcheck-world? The only failure we've run into at the moment is in the snapshot-too-old tests. Maybe we're not configuring with all the tests enabled? >> The assertion added caught at least one code path where TestForOldSnapshot >> calls PageGetLSN without holding any lock. The snapshot_too_old test in >> "check-world" failed due to the assertion failure. This needs to be fixed, >> see the open question in the opening mail on this thread. > > Good point. I am looping Kevin Grittner here for his input, as the > author and committer of old_snapshot_threshold. Things can be > addressed with a separate patch by roughly moving the check on > PageGetLSN() to TestForOldSnapshot_impl() and use BufferGetLSNAtomic() > instead. It still doesn't pass the tests, as not all code paths ensure that a content lock is held before calling TestForOldSnapshot. BufferGetLSNAtomic only adds the spinlock. > The commit fest has lost view of this entry, and so did I. So I have > added a new entry: > https://commitfest.postgresql.org/16/1371/ Thank you! > BufferGetLSNAtomic() could really use LWLockHeldByMe(). Could you > consider it with an extra patch on top of 0001? The LWLockHeldByMe() calls are added to BufferGetLSNAtomic in patch 0002 (because it does all its work through PageGetLSN). > It seems to me that 0001 is good for a committer lookup, that will get > rid of all existing bugs. For 0002, what you are proposing is still > not a good idea for anything using page copies. I think there is still significant confusion here. To be clear: this patch is intended to add no changes for local page copies. As I've tried to say (three or four times now): to our understanding, local page copies are not allocated in the shared BufferBlocks region and are therefore not subject to the new assertions. Am I missing a corner case, or completely misunderstanding your point? I never got a direct response to my earlier questions on this. --Jacob -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers