Re: 7.2 is slow?

> I haven't tested with the new 7.2 betas, but here are some results from
> 7.1.
> 
> We have a developement computer, IBM x series 250, with 4 processors
> (PIII Xeon 750Mhz), 1 Gb memory and  2SCSI disks (u160).
> 
> The software is writing new rows to a table, and after this it reads the
> id from that row. There are currently about 50 connections doing the
> same thing.
> 
> When I run this test with the Redhat 7.1, with SMP kernel, I noticed, that
> the
> processors are more than 90% idle. Disks utilisation is not the
> bottleneck either, since there is very low disk usage. Some data is
> written to disks every 4-5 seconds. Fsync is turned of. In transactions,
> this means about 200 inserted rows per second. The software that is used
> to give the feed, is capable of several thousand rows per second.
> 
> Okey, so I tried this also with the same computer, but using the not SMP
> supported kernel. So only with one processor. The result was about 600
> rows per second. The configuration file was unchanged. Now, the
> processor is about 100% utilized.
> 
> I didn't find any parameters that should help in this, but if you have a
> version of 7.2 that you would like to get information about, let me
> know, so I'll test.

Yes!  This sleeping case is the problem we expected to see on SMP
machines in >= 7.1 because of lock contention and a select() that can't
sleep for less than 1/100 second.  Please try the current 7.2 snapshot
and let us know what performance you get.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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