On Mon, 2007-09-10 at 22:24 -0400, 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 can calculate where they are, if thats the objection. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
