-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/24/07 14:48, Gregory Stark wrote: [snip] > > The main use case for it is actually REINDEX. Since you already have an index > which contains precisely the records you want to index and already in order > too. > > The main disadvantage is that it's not clear when it would actually be faster. > Generally index scans are slower than reading the whole table and sorting. > Probably it would have to run an SPI query to use the planner to find the best > way to get the rows it wants. I believe you, but it's totally counter to prima-fascia logic. Scanning the whole table means that you have to read in a whole bunch of columns that you don't really give a rat's arse about, and thus is a waste, whereas directly reading an existing index means that you've got perfect locality of data, since you're only reading what you care about. > Another problem is that presumably you're reindexing because the existing > index *isn't* in such good shape. You may even be doing it because the > existing index is corrupt. That, of course, is an excellent point. - -- Ron Johnson, Jr. Jefferson LA USA Give a man a fish, and he eats for a day. Hit him with a fish, and he goes away for good! -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGpqHkS9HxQb37XmcRAu93AKC04YXUWvMI6YiLfBNoy2BYtQw28ACdHqE/ kVqHiPwBONv0Tudy5OnA/SE= =Fbuw -----END PGP SIGNATURE-----
