On Tue, Feb 1, 2011 at 12:41 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> So I'm back to proposing that we just apply FPI-free WAL records >> unconditionally, without regard to the LSN. This could potentially >> corrupt the page, of course. > > Yes. So you're still assuming that there will be a later FPI-containing > WAL record to fix up the mess you created. What if there isn't?
In that case, the page shouldn't be corrupted. The possibility of corruption comes from the fact that a future WAL record might rearrange the page contents so that the current WAL record is no longer applying to the set of tuples it expects to be seeing. But any such action would necessarily induce an FPI. If there is no such action, then how can the page get into a state where replaying a heap delete will corrupt it? For that to happen, the item pointer list has to have changed. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
