HI all. I have a 8M+ rows table over which I run a query with a and-only WHERE condition. The table has been periodically VACUUMed and ANALYZEd. In the attempt of speeding that up I added a partial index in order to limit the size of the index. Of course that index is modeled after a "slowly variable" part of the WHERE condition I have in my query.
And timings actually dropped dramatically (I do know the problems with caching etc. and I paid attention to that) to about 1/20th (from about 800ms to average 40ms, actually). So I turned to EXPLAIN to see how the partial index was used. Incredibly, the partial index was not used! So I tried to drop the new index and incredibly the performances where still very good. While I can understand that the planner can decide not to use a partial index (despite in my mind it'd make a lot of sense), I'd like to understand how it comes that I get benefits from an enhancement not used! What'd be the explanation (if any) for this behavior? Thanks. -- Fahrbahn ist ein graues Band weisse Streifen, grüner Rand -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
