"Benjamin Krajmalnik" <kraj@xxxxxxxxxxxxx> writes: > A little background - I have various multi-column indexes whenever I > have queries which restrict the output based on the values of the 2 > fields (for example, a client code and the date of a transaction). > Is there a performance gain using this approach as opposed to using 2 > separate indexes, one on the first column and one on the second column? Maybe, maybe not ... it's going to depend on a bunch of factors, one of which is what your update load is like compared to the queries that read the indexes. There's a bit of coverage of this in the fine manual: see http://www.postgresql.org/docs/8.4/static/indexes-multicolumn.html and the next few pages. The short of it is that there's no substitute for doing your own experiments for your own application ... regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
