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Home -> Community -> Usenet -> c.d.o.server -> Re: lots of waiting on 'db file parallel write'
When I said that there are lots of waits on 'db file parallel write' I
should have said that a few times a day without any sort of consistency
I will noticed that 1 or all of my 4 db writers are hanging and waiting
on the 'db file parallel write' event to complete...the writers will
wait anywhere between 10-140 seconds and then they won't wait anymore
on that event for another couple of hours.. It's very intermitent.. but
when it happens the db writers might wait for the event 'db file
parallel write' for up to 140 seconds.. meaning the
v$SESSION_WAIT.seconds_in_wait may show up to 140 seconds of wait
time... Again I'm not monitoring this regularly yet, but I'd say that
during a business day this will happen 3-5 times...
Equally, the 'free buffer waits' might get lost in the AWR hourly report because this type of problem will only occur every so often..
I would say that because this type of problem is rare, when it happens the waits are extreme (in my opinion anything more than 1-2 seconds is extreme).
I'm planning on setting up a job to run every 5 minutes to get a feel for how often it really happens... But as I mentioned in my response to Joel, the load on our system can change dramatically from 1 minute to the next.
-peter Received on Mon Feb 27 2006 - 21:23:01 CST