I have a quick question. I feel like somewhere in section 23.1.6 there should be the answer but I couldn't find it yet. Namely how can I query the database for total number of tuples inserted, updated, or deleted since the last ANALYZE? pg_stat_user_tables.n_tup_{ins,upd,del,hot_upd} seems to not reset after an analyze[1]. But clearly the database has that knowledge somewhere persistent because otherwise how could autovacuum do its thing.
Rationale for the question. I have the strong suspicion that for some of our bigger tables autovacuum analyze is not hitting frequently enough (even so we already much more aggressive settings than the default). So I want to set some custom settings for those tables. But rather than doing it manually for the one table I found I would much rather write a query (ideally one taking any existing per table settings into account) that tells me likely candidates for tweaking. But so far I fail to even get the relevant data.
What you are looking for is the n_mod_since_analyze column of the pg_stat_user_tables view. It's available since the 9.4 release. If you have an earlier version, you need this extension: http://pgxn.org/dist/mods_since_analyze/1.0.0/
Ah excellent. Thanks. Sigh updating to 9.x with x > 2 has been a long time coming.
