Pavel Stehule escribió: > But question? > > about MVCC? > Is necessary to use MVCC on pg_statistic and some columns from pg_proc?
Right now, we use MVCC everywhere because we have no choice. But there are some things that would be better off not using MVCC; and indeed we use a hack to make things that way in certain, very limited cases (see callers of heap_update_inplace). Years ago I proposed a patch (search for pg_class_nt and/or pg_ntclass) that created a catalog for non-MVCC attributes, with an eye on extending it to more attributes. The use case for those other attributes had fatal flaws so it went nowhere, but perhaps we can give the idea another whirl now. For example I think it would be possible to implement read-only partitions that don't need vacuuming using that idea. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
