On 2013-06-14 09:21:52 -0400, Tom Lane wrote: > Heikki Linnakangas <hlinnakan...@vmware.com> writes: > > On 14.06.2013 16:08, Tom Lane wrote: > >> Refresh my memory as to why we need to WAL-log hints for checksumming? > > > Torn pages: > > So it's not that we actually need to log the individual hint bit > changes, it's that we need to WAL-log a full page image on the first > update after a checkpoint, so as to recover from torn-page cases. > Which one are we doing?
MarkBufferDirtyHint() loggs an FPI (just not via a BKP block) via XLogSaveBufferForHint() iff XLogCheckBuffer() says we need to by comparing GetRedoRecPtr() with the page's lsn. Otherwise we don't do anything besides marking the buffer dirty. 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
