On 2013-12-01 18:02:27 -0500, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > On 2013-12-01 17:15:31 -0500, Tom Lane wrote: > >> Is there really a significant risk of clog access errors due to this bug? > >> IIUC, the risk is that tuples in pages that vacuum skips due to being > >> all-visible might not be frozen when intended. > > > Unfortunately it's not actually too hard to hit due to following part of the > > code in vacuumlazy.c: > > > /* > > * If we're not scanning the whole relation to guard against XID > > * wraparound, it's OK to skip vacuuming a page. The next vacuum > > * will clean it up. > > */ > > Ah. So it's only been *seriously* broken since commit bbb6e559c, ie 9.2.
Well, even before that crash recovery/replication didn't necessarily preserve the hint bits. Even more so if somebody dared to set full_page_writes=off. I personally think full_page_writes=off should conflict with wal_level != minimal, btw, but I don't see much chance of gaining acceptance for that. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
