Tom Lane wrote: > Simon Riggs <[EMAIL PROTECTED]> writes: >> On Tue, 2007-09-11 at 01:22 +0530, Pavan Deolasee wrote: >>> I think the only difference is that the quick pruning does not mark >>> intermediate tuples ~LP_USED and hence we may avoid WAL logging. > >> Sounds great. > > What it sounds is utterly unsafe. You can get away with not WAL-logging > individual bit flips (that is, hint-bit-setting) because either state of > the page is valid. If I read this proposal correctly it is to change > t_ctid without WAL-logging, which means that a partial page write (torn > page syndrome) could leave the page undetectably corrupted --- t_ctid > is 6 bytes and could easily cross a hardware sector boundary.
We're only changing the offsetnumber part of it, which is 2 bytes. That shouldn't cross a hardware sector boundary on any reasonable hardware. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
