Re: Checkpoint cost, looks like it is WAL/CRC - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Checkpoint cost, looks like it is WAL/CRC
Date
Msg-id 17124.1122072861@sss.pgh.pa.us
Whole thread Raw
In response to Re: Checkpoint cost, looks like it is WAL/CRC  (Greg Stark <gsstark@mit.edu>)
List pgsql-hackers
Greg Stark <gsstark@mit.edu> writes:
> For any benchmarking to be meaningful you have to set the checkpoint interval
> to something more realistic. Something like 5 minutes. That way when the final
> checkpoint cycle isn't completely included in the timing data you'll at least
> be missing a statistically insignificant portion of the work.

This isn't about benchmarking --- or at least, I don't put any stock in
the average NOTPM values for the long-checkpoint-interval runs.  What we
want to understand is why there's a checkpoint-triggered performance
dropoff that (appears to) last longer than the checkpoint itself.  If
we can fix that, it should have beneficial impact on real-world cases.
But we do not have to, and should not, restrict ourselves to real-world
test cases while trying to figure out what's going on.
        regards, tom lane


pgsql-hackers by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: Autovacuum loose ends
Next
From: Tom Lane
Date:
Subject: Re: Checkpoint cost, looks like it is WAL/CRC