Adrian Moisey <adrian@xxxxxxxxxxxxxxxxxxxx> writes: >> we've found it: TRUNCATE > I haven't been following this thread. Can someone please explain to me > why TRUNCATE causes these spikes? It's not so much the TRUNCATE as the overhead of broadcasting the resultant catalog changes to the many hundreds of (mostly idle) backends he's got --- all of which respond by trying to lock the shared sinval message queue at about the same time. You could see the whole thread as an object lesson in why connection pooling is a good idea. But certainly it seems that sinval is the next bottleneck in terms of being able to scale Postgres up to very large numbers of backends. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
