Hello, At Thu, 26 Mar 2015 18:50:24 +0100, Andres Freund <and...@2ndquadrant.com> wrote in <20150326175024.gj...@alap3.anarazel.de> > I think the problem here is that the *primary* makes no such > assumptions. Init forks are logged via stuff like > smgrwrite(index->rd_smgr, INIT_FORKNUM, BTREE_METAPAGE, .. > i.e. the data is written out directly to disk, circumventing > shared_buffers. It's pretty bad that we don't do the same on the > standby. For master I think we should just add a bit to the XLOG_FPI > record saying the data should be forced out to disk. I'm less sure > what's to be done in the back branches. Flushing every HEAP_NEWPAGE > record isn't really an option.
The problem exists only for INIT_FORKNUM. So I suppose it is enough to check forknum to decide whether to sync immediately. Specifically for this instance, syncing buffers of INIT_FORKNUM at the end of XLOG_FPI block in xlog_redo fixed the problem. The another (ugly!) solution sould be syncing only buffers for INIT_FORKNUM and is BM_DIRTY in ResetUnlogggedRelations(op = UNLOGGED_RELATION_INIT). This is catching-all-at-once solution though it is a kind of reversion of fast promotion. But buffers to be synced here should be pretty few. regards, -- Kyotaro Horiguchi NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
