On Tue, 21 May 2019 at 08:23, Jeremy Altavilla <jeremyaltavilla@xxxxxxxxx> wrote: > > Thanks for the suggestion. I created extended statistics objects for the two tables in question. Unfortunately the resulting plan was the same (and had the same estimates). It looks like the extended stats discovered a potentially useful correlation on bag: "2, 3 => 1" (owner_id, bag_type_id => id). I'm guessing this wasn't usable because the docs state "They are not used to improve estimates for equality conditions comparing two columns". I'd say that since the time spent planning is near 3x what is spent during execution that you're wasting your time trying to speed up the execution. What you should be thinking about is using PREPAREd statements to avoid the planning overhead completely. If that's not possible then you've more chance of reducing the time spent planning by reducing the statistics on the table rather than adding more planning overhead by adding extended stats. You might want to experiment with ALTER TABLE ... ALTER COLUMN ... SET STATISTICS ..; and setting those down a bit then analyzing the tables again. Although, that's likely only going to make a very small difference, if any, than getting rid of the planning completely. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
