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Re: sql-bench

From: yoav x <yoav112003(at)yahoo(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: sql-bench
Date: 2006-09-14 06:55:22
Message-ID: 20060914065522.23041.qmail@web35806.mail.mud.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-performance
You can use the test with InnoDB by giving the --create-options=engine=innodb option in the
command line. Even with InnoDB, in some specific tests PG looks very bad compared to InnoDB.

--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> yoav x <yoav112003(at)yahoo(dot)com> writes:
> > Are there any tuning parameters that can be changed to speed these
> > queries? Or are these queries especially tuned to show MySQL's
> > stgrenths?
> 
> The latter.  I've ranted about this before --- there are both obvious
> and subtle biases in that benchmark.  The last time I spent any time
> with it, I ended up testing with these nondefault settings:
> 
> shared_buffers = 10000          
> work_mem = 100000               
> maintenance_work_mem = 100000   
> fsync = false                   
> checkpoint_segments = 30        
> max_locks_per_transaction = 128
> 
> (fsync = false is pretty bogus for production purposes, but if you're
> comparing to mysql using myisam tables, I think it's a reasonably fair
> basis for comparison, as myisam is certainly not crash-safe.  It'd be
> interesting to see what mysql's performance looks like on this test
> using innodb tables, which should be compared against fsync = true
> ... but I don't know how to change it to get all the tables to be
> innodb.)
> 
> Also, on some of the tests it makes a material difference whether you
> are using C locale or some other one --- C is faster.  And make sure you
> have a recent version of DBD::Pg --- a year or two back I recall seeing
> the perl test program eating more CPU than the backend in some of these
> tests, because of inefficiencies in DBD::Pg.
> 
> IIRC, with these settings PG 8.0 seemed to be about half the speed of
> mysql 5.0 w/myisam, which is probably somewhere in the ballpark of the
> truth for tests of this nature, ie, single query stream of fairly simple
> queries.  If you try concurrent-update scenarios or something that
> stresses planning ability you may arrive at different results though.
> I have not retested with more recent versions.
> 
> 			regards, tom lane
> 
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