Hi, On Tue, Jan 15, 2019 at 10:22 AM Thomas Güttler <guettliml@xxxxxxxxxxxxxxxxxx> wrote: > > Hi Julien Rouhaud, > > powa can handle multi-column indexes now? Great news. This must be a new > feature. I checked this roughly one year ago and it was not possible at this time. > Thank you very much powa! Oh, that's unexpected. The first version of the "wizard" (the "optimize this database" button on the database page) we published was supposed to handle multi-column indexes. We had few naive tests for that, so at least some cases were working. What it's doing is gathering all the quals that have been sampled by pg_qualstats in the given interval on the given database, and then try to combine them (possibly merging a single column qual into a multi-column qual), order them by number of distinct queryid so it can come up with a quite good set of indexes. So if there are queries with multiple AND-ed quals on the same table in your workload, it should be able to suggest a multi-column index. If it doesn't, you should definitely open a bug on the powa-web repo :) What it won't do is to suggest to replace a single column index with a multi-column one, or create a multi-column index if one of the column is already indexes since only one of the column will be seen as needing optimization.
