[wplug] Apache/Mysql performance question ...

[chris.romano at verizon.net]

> From: Bill Moran <wmoran at potentialtech.com>
> Date: 2004/08/16 Mon PM 03:08:45 EDT
> To: General user list <wplug at wplug.org>
> CC: vze2f6h6 at verizon.net
> Subject: Re: [wplug] Apache/Mysql performance question ...
> 
> "Chris" <vze2f6h6 at verizon.net> wrote:
> > We have a RH 7.3 box that isn't doing much but host a few websites.
> > These sites are very dynamic and are doing a log of queries via PHP, but
> > the stats below seem a little high.  Does apache or MySQL usually take
> > up about 10M of RAM per connection/child?  I know that I haven't given
> > that much info but does something look wrong or is this typical?
> 
> Are you having actual performance problems?

No. top just didn't seem right to me.
 
> This isn't unusual.  Keep in mind a few things:
> 1) The kernel will use all the memory available to buffer data.  In the
>    case that memory becomes scarce, buffered data can be converted to
>    free memory with almost no overhead.  The fact that you've got less
>    than 1M of swap in use tells me that it's not running low on RAM
>    much.

That makes sense.

> On the other side of the argument:
> If you do big queries, PHP will store the entire contents of the result
> in RAM.  This can take up a huge amount of RAM.  In fact, the easiest
> way I know of to cause PHP to suck up all the ram is to do a SELECT *
> FROM some_huge_table.  So there _may_ be a a problem in you PHP code
> that can optimize away some of this RAM usage.

Yeah, that's why I try to stay away from "SELECT *"

Thanks for insight.

Chris