Dimitri Fontaine escribió: > Alvaro Herrera <alvhe...@commandprompt.com> writes: > > Dimitri Fontaine escribió: > >> Why can't MVCC apply here? You'd have two versions of the pg_class entry > >> that just has been CLUSTERed, and you keep the old relfilenode arround > >> too. MVCC applies, and you teach vacuum to clean out the old file when > >> cleaning out the no more visible tuple. > > > > It just doesn't work. pg_class (and various other rels) are special > > because they are needed to bootstrap the catalog system. See > > RelationCacheInitializePhase3. It wouldn't be possible to figure out > > what's pg_class relfilenode until you have read it from pg_class, which > > is precisely what we're trying to do. > > Well at bootstrap time I guess noone is able to disturb the system by > placing a concurrent CLUSTER pg_class; call. Once started, do those rels > still need to have a special behavior?
The relcache need to be bootstrapped more than once, not just at initdb's bootstrap. (I guess you could try a breakpoint in formrdesc) > I guess I'm being dense, will now let people in the know find a solution... Yeah, well, Tom just posted a possible solution :-) -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers