On Mon, Apr 08, 2019 at 04:33:34PM +0200, Pavel Stehule wrote: > po 8. 4. 2019 v 16:11 odesílatel Krzysztof Plocharz <plocharz@xxxxxxxxxxxxxx> napsal: > > > We have some very strange query planning problem. Long story short it > > takes 67626.278ms just to plan. Query execution takes 12ms. > > > > Query has 7 joins and 2 subselects. > > It looks like the issue is not deterministic, sometimes is takes few ms > > to plan the query. > > > > One of the tables has 550,485,942 live tuples and 743,504,012 dead > > tuples. Running ANALYZE on that tables solves the problem only temporarily. > > > > Question is how can we debug what is going on? > > please check your indexes against bloating. Planner get min and max from > indexes and this operation is slow on bloat indexes. I think that's from get_actual_variable_range(), right ? If it's due to bloating, I think the first step would be to 1) vacuum right now; and, 2) set more aggressive auto-vacuum, like ALTER TABLE t SET (AUTOVACUUM_VACUUM_SCALE_FACTOR=0.005). What version postgres server ? Justin
