Claudio Freire <klaussfreire@xxxxxxxxx> writes: > On Mon, Oct 31, 2011 at 2:08 PM, Robert Haas <robertmhaas@xxxxxxxxx> wrote: >>> Multicolumn indices on (c1, c2, ..., cn) can only be used on where >>> clauses involving c1..ck with k<n. >> I don't think that's true. I believe it can be used for a query that >> only touches, say, c2. It's just extremely inefficient. > Does postgres generate those kinds of plans? Sure it does. It doesn't usually think they're efficient enough, because they require full-index scans. But sometimes that's the best you can do. 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
