On Mon, Nov 21, 2011 at 6:14 PM, Tomas Vondra <t...@fuzzy.cz> wrote: ..... >> >> An index on (a, b) can be used for queries involving only a but not for >> those involving only b. > > That is not true since 8.2 - a multi-column index may be used even for > queries without conditions on leading columns. It won't be as effective as > with conditions on leading columns, because the whole index must be > scanned, but it's usually much cheaper than keeping two indexes (memory > requirements, overhead when inserting data etc.) > > Check this: > http://www.postgresql.org/docs/8.2/interactive/indexes-multicolumn.html
Thanks Tomas. VERY useful information. I've decided to go with a unique multicolumn index for now. Will ask the experts here if I see some issues.. Thanks! -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
