On Tue, 19 Mar 2002, Oleg Bartunov wrote: Sorry to reply over you, Oleg.
> On 13 Mar 2002, Greg Copeland wrote: > > > One of the reasons why I originally stated following the hackers list is > > because I wanted to implement bitmap indexes. I found in the archives, > > the follow link, http://www.it.iitb.ernet.in/~rvijay/dbms/proj/, which > > was extracted from this, > > >http://groups.google.com/groups?hl=en&threadm=01C0EF67.5105D2E0.mascarm%40mascari.com&rnum=1&prev=/groups%3Fq%3Dbitmap%2Bindex%2Bgroup:comp.databases.postgresql.hackers%26hl%3Den%26selm%3D01C0EF67.5105D2E0.mascarm%2540mascari.com%26rnum%3D1, > archive thread. For every case I have used a bitmap index on Oracle, a partial index[0] made more sense (especialy since it could usefully be compound). Our troublesome case (on Oracle) is a table of "events" where maybe fifty to a couple of hundred are "published" (ie. web-visible) at any time. The events are categorised by sport (about a dozen) and by "event type" (about five). We never really query events except by PK or by sport/type/ published. We make a bitmap index on "published", and trust Oracle to use it correctly, and hope that our other indexes are also useful. On Postgres[1] we would make a partial compound index: create index ... on events(sport_id,event_type_id) where published='Y'; Matthew. [0] Is this a postgres-only feature; my tame Oracle and Sybase DBAs had never heard of such a thing, but were rather impressed at the idea. [1] Disclaimer. Our system doesn't run on PG, though I do have a nearly equivalent prototype system which does. I'd love to hear any success (or otherwise) stories about PG partial indexes. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
