[wirelesstoronto-discuss] tech help needed!

[James Walker]

If apache is creating load - it might be the PHP execution - I'd  
recommend installing APC (a PHP opcode cache) to help alleviate any  
PHP overhead being incurred. I don't know the auth system well, but  
it's typically a big, easy win for PHP-based apps.

more info here : http://pecl.php.net/package/APC

Cheers,
j

On 16-Apr-08, at 4:48 PM, Rob Janes wrote:
> the indexes should be setup already.  i don't think there's any  
> tuning needed there.  gabe will have followed the isf install script.
>
> i'm thinking one of the nodes is sending too much heartbeat.  that's  
> why i suggested looking in the logs.
>
> you could check the postgres logs.  postgres gets real busy when it  
> flushes it's logs, and it can bog down the machine.  it shouldn't be  
> doing that very often, it's a bursty thing.  gabe is saying the  
> meter is pegged at 4 or so.  if postgres was busying up the system  
> on it's own, due to a misconfiguration or misbalancing of the  
> database files and the log files, it would show low load most of the  
> time, then flipping over to some high number.
>
> postgres can be set to log all sql that comes in.  in a more verbose  
> mode it could indicate what the problem is.
>
> On Wed, Apr 16, 2008 at 4:38 PM, Jon Pounder <Jon at pounder.com> wrote:
> Quoting Rob Janes <janes.rob at gmail.com>:
>
> did you do vacuumdb -full, or VACUUM FULL;  that frees up empty  
> deleted
> records.  it won't speed up queries, which may be the problem.   
> VACUUM FULL
> and vacuumdb -full lock tables, so there will be an outage when you do
> this.  best to do it early in the morning.
>
> if there are tons dead rows it does speed things up significantly  
> since the live rows fit into far less physical pages on disk so net  
> result you reduced the disk reads needed to do a given amount of work.
>
> make sure you have it on automatic though and then you don't have to  
> remember to do it.
>
> apache could also be showing busy depending how efficient the waits  
> are on postgres in the particular postgres client driver you are  
> using. apache and pg could also be competing for disk read bandwidth  
> and both waiting on that when pg is doing something intense.
>
> I kind of got into this group late so not sure what the auth server  
> is actually using, but if its not a tried and tested system, its  
> possible it needs some indexes to fix access speed on tables that  
> started out small and now are huge.
>
>
>
>
>
> however, that apache is busy too suggests something akin to a dos.   
> check
> the apache logs.
>
> -rob
>
> On Wed, Apr 16, 2008 at 3:59 PM, Gabe Sawhney <gabe at pwd.ca> wrote:
>
> Top seems to indicate that the problem is with apache and postgres,  
> but I
> don't know what the numbers mean.  I took Jon's suggestion and ran a  
> VACUUM
> ANALYZE again (I thought I'd done several times before), and it  
> cooled it
> down a bunch... now the load avg is between 4 and 5.  That still  
> strikes me
> as high, but it's a lot better.  I'll keep an eye on it in the next  
> few
> days.
>
> The machine had 638 days uptime until I rebooted it today, trying to
> troubleshoot this.  (The reboot didn't help.)
>
> Gabe
>
>
>
> On Wed, Apr 16, 2008 at 3:39 PM, Rob Janes <janes.rob at gmail.com>  
> wrote:
>
> > what does top say?
> >
> > do you want me to log on to the box?
> >
> > -rob
> >
> >
> > On Wed, Apr 16, 2008 at 2:50 PM, Jon Pounder <Jon at pounder.com>  
> wrote:
> >
> > > Quoting Gabe Sawhney <gabe at pwd.ca>:
> > >
> > >  We need some help from someone with Linux performance tuning
> > > > experience.
> > > > Our auth server in the past few months has been getting really
> > > > slow... we
> > > > haven't been asking it to do any more work, but while before the
> > > > load
> > > > average sat around 1.1, now it's almost always between 6 and  
> 12(!).
> > > >
> > > > Basically we're talking about Apache, PHP5 and Postgresql.   
> There's
> > > > also
> > > > MySQL and Mailman running on the box, but I doubt those have
> > > > anything to do
> > > > with it.
> > > >
> > > > If you've done stuff like this before, please get in touch!
> > > >
> > >
> > >
> > > make sure postgres is configured to autovacuum tables.
> > >
> > > if you don't have it, install pgadmin on your own desktop  
> (windows)
> > > and connect to the pg db as the postgres user, then you can fine  
> tune
> > > whatever you need on there.
> > >
> > > also look for any log files that have just gotten massive, and  
> clean
> > > them out.
> > >
> > > if its not been rebooted in a while (like months), also do that  
> which
> > > will force a check of the drives in case anything is haywire  
> there.
> > >
> > >
> > > also - btw, the listserver for this mailing list is broken,  
> messages
> > > are addressed to the list rather than the person when they  
> arrive so
> > > replying if you have multiple email accounts is broken.
> > >
> > >
> > >
> > > > Gabe
> > > >
> > > >
> > >
> > >
> > >
> > >
> > > Jon Pounder
> > >
> > >
> > > _______________________________________________
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> > >
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> > >
> >
> >
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> >
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> Jon Pounder
>
>
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James Walker :: http://walkah.net/ :: xmpp:walkah at walkah.net