Stelios Mavromichalis wrote >> the load of the machine is also low (like 0.2). Which means little if the update is waiting for a lock to be released by one other process; which is more likely the situation (or some other concurrency contention) especially as you said that this particular user generates significant transaction/query volume (implied by the fact the user has the most balance updates). During slow-update executions you want to look at: pg_stat_activity pg_locks to see what other concurrent activity is taking place. It is doubtful that dump/restore would have any effect given that the symptoms are sporadic and we are only talking about a select statement that returns a single row; and an update that does not hit any indexed column and therefore benefits from "HOT" optimization. HTH David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Re-recently-and-selectively-slow-but-very-simple-update-query-tp5802553p5802555.html Sent from the PostgreSQL - performance mailing list archive at Nabble.com. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
