Torsten Förtsch wrote on 20.04.2014 10:09:
The problem is I have a number of indexes in a large system that are very similar. And I suspect some of them are superfluous.Example: btree (fmb_id, action_type) btree (fmb_id) Action_type in this case is one out of a handful of values (should perhaps be an ENUM but is TEXT) and for most of the table the combination of (fmb_id, action_type) is unique. The table itself has ~2E8 rows. So it takes a while to build these indexes from scratch. Now, we have several performance counters in place. I want to disable these indexes one by one and see what happens. I am probably not able to find all of the queries that use them. But I believe that nothing much happens if I drop one of them (preferably the former?).
What about monitoring pg_stat_all_indexes to see if an index is used: http://www.postgresql.org/docs/current/static/monitoring-stats.html#PG-STAT-ALL-INDEXES-VIEW Btw: in the above example the second one is definitely not needed. Any query that uses the second one (single column) can also use the first one. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
