NYCPHP Meetup

[Adam Maccabee Trachtenberg]

On Wed, 21 Jul 2004, George Schlossnagle wrote:

> On Jul 21, 2004, at 2:59 PM, Mitch Pirtle wrote:

> > Something I have learned while doing my own testing is that using
> > ADOdb's query cache (which caches on the webserver, not in the
> > database like MySQL) provides significant performance benefits, UNLESS
> > your webserver is working harder than the database machine, in which
> > case it will actually hurt.
>
> Just as a note (or to start a good-natured debate), the real problem
> with client-side caches is maintaining a consistent view in a
> multi-server environment.

That's a good point.

At TVGrid.Com, we separated our data into two bins:

1) Data that was constantly being updates (such as membership info)

2) Data that was updated once per day (what's on tv tonight?).

That allowed us to implement a simple client-side SQL cache for bin #2
over multiple web server without too many worries.

Of course, I don't think we ended up hitting the cache too often
because our data was so spread out. People just didn't search for the
same thing all that often (and when they did, if they were in
differing locations, we returned different data, so we couldn't use
the cache.)

So that's another point to consider, the effectiveness of your cache
is directly related to your dataset and typical usage.

-adam

-- 
adam at trachtenberg.com
author of o'reilly's "upgrading to php 5" and "php cookbook"
avoid the holiday rush, buy your copies today!