Message-ID: <44699C6C.80302@tweakers.net>
Date: Tue, 16 May 2006 11:33:32 +0200
From: Arjen van der Meijden <acmmailing@tweakers.net>
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To: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Pgsql (and mysql) benchmark on T2000/Solaris and some profiling
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Hi List,

In the past few weeks we have been developing a read-heavy 
mysql-benchmark to have an alternative take at cpu/platform-performance. 
Not really to have a look at how fast mysql can be.

This benchmark runs on mysql 4.1.x, 5.0.x and 5.1.x and is modelled 
after our website's production database and the load generated on it is 
modelled after a simplified version of our visitor behaviour.

Long story short, we think the test is a nice example of the relatively 
lightweight, read-heavy webapplications out there and therefore decided 
to have a go at postgresql as well.
Of course the queries and indexes have been adjusted to (by our 
knowledge) best suit postgresql, while maintaining the same output to 
the application/interface layer. While the initial structure only got 
postgresql at about half the performance of mysql 4.1.x, the current 
version of our postgresql-benchmark has quite similar results to mysql 
4.1.x, but both are quite a bit slower than 5.0.x (I think its about 
30-40% faster).

Since the results from those benchmarks are not yet public (they will be 
put together in a story at our website), I won't go into too much 
details about this benchmark.

Currently we're having a look at a Sun T2000 and will be looking at will 
be looking at other machines as well in the future. We are running the 
sun-release of postgresql 8.1.3 on that T2000 now, but are looking at 
compiling the cvs-head version (for its index-root-cache) somewhere this 
week.

My guess is there are a few people on this list who are interested in 
some dtrace results taken during our benchmarks on that T2000.
Although my knowledge of both Solaris and Dtrace are very limited, I 
already took some samples of the system and user calls. I used Jignesh 
Shah's scripts for that: 
http://blogs.sun.com/roller/page/jkshah?entry=profiling_postgresql_using_dtrace_on

You can find the samples here:
http://achelois.tweakers.net/~acm/pgsql-t2000/syscall.log
http://achelois.tweakers.net/~acm/pgsql-t2000/usrcall.log

And I also did the memcpy-scripts, here:
http://achelois.tweakers.net/~acm/pgsql-t2000/memcpysize.log
http://achelois.tweakers.net/~acm/pgsql-t2000/memcpystack.log
(this last log is 3.5MB)

If anyone is interested in some more dtrace results, let me know (and 
tell me what commands to run ;-) ).

Best regards,

Arjen