Re: [PERFORM] Sun Donated a Sun Fire T2000 to the PostgreSQL

Hi,

Tom Lane schrieb:
> Robert Lor <Robert.Lor@Sun.COM> writes:
>> I ran pgbench and fired up a DTrace script using the lwlock probes we've
>> added, and it looks like BufMappingLock is the most contended lock, but
>> CheckpointStartLocks are held for longer duration!
>
> Those numbers look a bit suspicious --- I'd expect to see some of the
> LWLocks being taken in both shared and exclusive modes, but you don't
> show any such cases.  You sure your script is counting correctly?
> Also, it'd be interesting to count time spent holding shared lock
> separately from time spent holding exclusive.

Is there a test case which shows the contention for this full cached
tables? It would be nice to have measurable numbers like context
switches and queries per second.

Sven.