On 2013-12-01 13:33:42 +0100, Andres Freund wrote: > On 2013-11-27 14:53:27 -0500, Noah Misch wrote: > > How would you characterize the chances of this happening with default > > *vacuum_freeze_*_age settings? Offhand, it seems you would need to > > encounter > > this bug during each of ~10 generations of autovacuum_freeze_max_age before > > the old rows actually become invisible. > > On second thought, it's quite possible to see problems before that > leading to more problems. A single occurance of such a illegitimate > increase in relfrozenxid can be enough to cause problems of a slightly > different nature. > As relfrozenxid has been updated we might now, or after vacuuming some > other tables, become elegible to truncate the clog. In that case we'll > get ERRORs about "could not access status of transaction" if the tuple > hasn't been fully hinted when scanning it later.
And indeed, a quick search shows up some threads that might suffer from it: bd7ee863f673a14ebf99d95562aee15e44b1d...@digi-pdc.digitilitiprod.int caazpmnxfdrv72wdmbev5tcqobye_wvgseqrkqj0fizxmcyy...@mail.gmail.com cak9ovjwvazlmdmrhmpg1+s37z16j+bz8fbarzspmrhsxxh-...@mail.gmail.com 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
