Robert Haas <robertmh...@gmail.com> writes: > On Tue, May 10, 2011 at 12:57 PM, Simon Riggs <si...@2ndquadrant.com> wrote: >> Hmmm, do we really need to WAL log freezing?
> That might solve the relfrozenxid problem - set the bits in the heap, > sync the heap, then update relfrozenxid once the heap is guaranteed > safely on disk - but it again seems problematic for Hot Standby. ... or even warm standby. You basically *have to* WAL-log freezing before you can truncate pg_clog. The only freedom you have here is freedom to mess with the policy about how soon you try to truncate pg_clog. (Doing an unlogged freeze operation first is right out, too, if it causes the system to fail to perform/log the operation later.) regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers