At 12:49 AM 5/2/02 -0400, Tom Lane wrote: >Lincoln Yeoh <[EMAIL PROTECTED]> writes: > > But does Postgresql visit the older tuples first moving to the newer ones, > > or the newer ones first? > >It's going to visit them *all*. Reordering won't improve the >performance.
Ack! I thought it went through them till the first valid tuple and was just going the wrong way. >FWIW I think that with the present implementation of btree, the newer >tuples actually will be visited first --- when inserting a duplicate >key, the new entry will be inserted to the left of the equal key(s) >already present. But it doesn't matter. The only way to speed this >up is to eliminate some of the visitings, which requires keeping more >info in the index than we presently do. OK I'm starting to get it :). Will the index behaviour be changed soon? Hmm, then what are the row tuple forward links for? Why forward? Regards, Link. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
