On Mon, 2007-03-05 at 22:25 +0530, Pavan Deolasee wrote: > Simon Riggs wrote: > > On Mon, 2007-03-05 at 21:39 +0530, Pavan Deolasee wrote: > > > > Currently each tuple is moved individually. You'd need to inspect the > > whole HOT chain on a page, calculate space for that and then try to move > > them all in one go. I was originally thinking that would be a problem, > > but its not so bad - but it may cause us to end repair_frag() earlier > > than we otherwise would depending upon the game of Tetris plays out. > > > > > Umm.. I still need to look deeper to understand the VACUUM FULL code, > but ISTM > that we can move tuple chains just the way its done today, without > bothering to keep > HOT-update chains intact. The tuples may actually got into different > pages and have > equal number of index entries. To my mind, this is not such a big > problem because > we shouldn't expect too many HOT-update chains while running VACUUM FULL. > Isn't that true ?
Well, its true enough to be a great argument. So what you're saying is: we do nothing and it just works. At least not too badly, and at very least: no worse than it does today. [Oh dear! I just finished writing prototype of VACUUM FULL-with-reindex when I read this, so either way it looks like nothing more needed on this utility. 1 down, 3 to go.] -- Simon Riggs EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend