what are normal ways to scale up PHP's default settings for growing traffic?

[lkrubner]

PHP comes with certain defaults, set in php.ini. Among these, scripts
time out after 60 seconds, I think. The default memory limit for a
script is, I believe, 8 megs.

I assume that when people do large-scale sites with PHP they scale
these numbers up. If you have a content management system running every
aspect of a large corporate web site, including a database back end
that employees use for important, secret, protected information, then I
imagine there is quite a lot of processing that might be needed for
every request.

A limit that I run into all the time is the memory limit. If I get a
large amount of info back from the database, and then try to store the
return in an array, it is easy to go over the default 8 meg limit.

So is it normal to scale up the default numbers? If so, by how much?

[Gordon Burditt]

>PHP comes with certain defaults, set in php.ini. Among these, scripts

time out after 60 seconds, I think. The default memory limit for a
script is, I believe, 8 megs.

I assume that when people do large-scale sites with PHP they scale
these numbers up. If you have a content management system running every
aspect of a large corporate web site, including a database back end
that employees use for important, secret, protected information, then I
imagine there is quite a lot of processing that might be needed for
every request.
Just because the site is large doesn't mean more processing for
every request. Just because the site is small with only one user
doesn't mean it won't have huge result sets that won't fit in 8 meg
or do a bunch of crunching that will take an hour of CPU time. And
the CPU time limits don't apply to how much CPU time your database
queries use in the database process.
A limit that I run into all the time is the memory limit. If I get a
large amount of info back from the database, and then try to store the
return in an array, it is easy to go over the default 8 meg limit.
There's no way you can limit the result set further? (In MySQL,
if you want to paginate the output to, say, 10 items per page, the
LIMIT clause can be used to retrieve only those 10 items rather
than all of them, and then you only display the appropriate 10).
Of course, there are plenty of reasons you might need to see all
the data anyway. If it's not practical to limit the data retrieved,
then you need the memory, and I see nothing wrong setting the limit
higher.

Setting the CPU limit to very high numbers (e.g. 5 minutes and
upwards) when this is actually needed is likely to mean unsatisfied
users unless they are told (repeatedly) that it's normal for the
page to take a huge amount of time to display. Give them some
progress indication. Otherwise they keep aborting the request and
you'll have dozens of the same request running at once.
So is it normal to scale up the default numbers? If so, by how much?

Having a lot of users, a lot of requests per hour, and a lot of
pages is not much of a reason to up these limits. Having pages
that actually *NEED* the limits raised to function is a good reason
to raise the limits. The limits are essentially there to protect
against errors like infinite loops from dragging the whole site
down with it. Seat belts save lives but not if they are adjusted
so tight you can't breathe.

Gordon L. Burditt

[Colin McKinnon]

lk******@geocit ies.com wrote:

PHP comes with certain defaults, set in php.ini. Among these, scripts
time out after 60 seconds, I think. The default memory limit for a
script is, I believe, 8 megs.
<snip>
So is it normal to scale up the default numbers? If so, by how much?

No. If you're trying to cope with more traffic, then increasing the
resources which can be used by each process, and the length of time it can
hold on to the processes can only *reduce* the volume of traffic it can
cope with.

If these limits are causing problems you need to look elsewhere for the
answer.

If you just want to process more traffic, then follow the standard recipes
for tuning your webserver, and install a PHP accelerator (Zend, IonCude,
Turck etc).

HTH

C.