Claudio Freire <klaussfreire@xxxxxxxxx> wrote: > On Thu, Apr 12, 2012 at 3:41 PM, Brian Fehrle > <brianf@xxxxxxxxxxxxxxxxxxx> wrote: >> This morning, during our nightly backup process (where we grab a >> copy of the data directory), we started having this same issue. >> The main thing that I see in all of these is a high disk wait on >> the system. When we are performing 'well', the %wa from top is >> usually around 30%, and our load is around 12 - 15. This morning >> we saw a load 21 - 23, and an %wa jumping between 60% and 75%. >> >> The top process pretty much at all times is the WAL Sender >> Process, is this normal? > > Sounds like vacuum to me. More particularly, it seems consistent with autovacuum finding a large number of tuples which had reached their freeze threshold. Rewriting the tuple in place with a frozen xmin is a WAL-logged operation. -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
