From: Joe Van Dyk <joevandyk@...>
Date: 2005-09-10T00:04:19+09:00
Subject: Re: general performance question

That's odd that it would take so long with only 20 records in the
result set.  With 140k in the result set, that would be expected, I
suppose.  But not 20.

Are you using the C mysql bindings, or the pure Ruby bindings?

On 9/9/05, Brian Le Roy <brian@le-roy.org> wrote:
> Thanks Robert!
> 
> I think I found the culprit.
> 
> With 20 records in the result:
> total ms/call
> 12300.00  Mysql::Result#each
> 
> With 1 record in the result:
> total ms/call
> 600.00  Mysql::Result#each
> 
> The query behind this result set is indexed properly.  Not sure why this
> takes so long - shouldn't it be as fast as a regular array.each call?
> 
> Robert Klemme wrote:
> > Brian Le Roy wrote:
> >
> >>Actually guys, I took out the queries - except for one that is run
> >>  once. Same behaviour in top.  I'm going to start marking out the
> >>app with
> >>the benchmark module and hopefully that will shed some light on it!
> >
> >
> > Note also that there is ruby -r profile.  That way you don't have to
> > manually change your code.
> >
> >     robert
> >
> >
> >>Robert Klemme wrote:
> >>
> >>>Reid Thompson <reid.thompson@ateb.com> wrote:
> >>>
> >>>
> >>>>Brian Le Roy wrote:
> >>>>
> >>>>
> >>>>>no, but the table has 140K records.  the disk isn't crunching, so
> >>>>>the index should be okay.  i was thinking it would be passing
> >>>>>around the database connection object causing overhead.  i took
> >>>>>the result set object and created a straight ol' array for
> >>>>>passing.  no improvement - so maybe there's nothing to do.  thanks
> >>>>>for all the responses - i'll keep messing with it and if i find
> >>>>>something that improves it, i'll let you know!
> >>>>>
> >>>>>bonefry wrote:
> >>>>>
> >>>>>
> >>>>>>Well, that's it.
> >>>>>>
> >>>>>>MySql can take even 100% of your processing power. It happenes
> >>>>>>when you have complex queries to run, and you run them on big
> >>>>>>tables. Are you running complex queries ?
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>It may may no difference, but you could try the same with
> >>>>postgresql, or maybe even sqlite, to see if it is mysql thats the
> >>>>issue.
> >>>
> >>>
> >>>Before he does that I'd try a different query frontend to see whether
> >>>performance characteristics stay the same (i.e. time is spent in the
> >>>DB, which would be my guess).  The overhead is much smaller compared
> >>>to installing another DBMS, transferring DDL and data to that.
> >>>
> >>>Kind regards
> >>>
> >>>   robert
> >
> >
> >
> >
> 
>