On Tue, Oct 17, 2017 at 12:23 PM, Peter Geoghegan <p...@bowt.ie> wrote: > On Tue, Oct 17, 2017 at 3:40 AM, Alvaro Herrera <alvhe...@alvh.no-ip.org> > wrote: >> Peter Geoghegan wrote: >> >>> Wouldn't this last "if" test, to cover the pg_upgrade case, be better >>> targeted by comparing *raw* xmin to FrozenTransactionId? You're using >>> the potentially distinct xmin value returned by >>> HeapTupleHeaderGetXmin() for the test here. I think we should be >>> directly targeting tuples frozen on or before 9.4 (prior to >>> pg_upgrade) instead. >> >> I also realized we can stop checking (i.e. don't compare xmin to >> frozenxid) if the XMIN_FROZEN bits are set -- because in that case the >> tuple cannot possibly come from 9.3 frozen. So I think this should do >> it. >> >> (New HeapTupleUpdateXmaxMatchesXmin() implementation) > > Yeah, this is what I had in mind, too.
BTW, seems worth fixing this old comment above heap_prepare_freeze_tuple() while you're at it: * NB: It is not enough to set hint bits to indicate something is * committed/invalid -- they might not be set on a standby, or after crash * recovery. We really need to remove old xids. -- Peter Geoghegan -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
