On 2013-05-28 09:39:13 -0700, Josh Berkus wrote: > On 05/28/2013 06:21 AM, Robert Haas wrote: > > As a general statement, I view this work as something that is likely > > needed no matter which one of the "remove freezing" approaches that > > have been proposed we choose to adopt. It does not fix anything in > > and of itself, but it (hopefully) removes an objection to the entire > > line of inquiry. > > Agreed. I have some ideas on how to reduce the impact of freezing as > well (of course), and the description of your approach certainly seems > to benefit them, especially as it removes the whole "forensic > information" objection. > > One question though: if we're not removing the xmin, how do we know the > maximum xid to which we can prune clog? I can imagine several ways > given your approach.
Simply don't count xids which are frozen. Currently we ignore an xid because its a special value, after this because the tuple has a certain hint bit (combination) set. 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
