[wp-hackers] MySQL MEMORY worth using for an object cache?

[Robert Deaton]

On 4/17/07, Matt Mullenweg <m at mullenweg.com> wrote:
> Robert Deaton wrote:
> > 4). Full page to disk caching does more harm than good on a server
> > that is expecting a beating, especially one like digg or slashdot. The
> > reason for this is that often times so many comments are posted that
> > the server is constantly having to regenerate these pages and write
> > them back to disk.
>
> My experience has been the opposite. Make sure you have the latest
> wp-cache, a previous had a bug where it would invalidate the cache for
> spam comments and comments stuck in moderation. Perhaps turning
> moderation in the situation would help as well, but I've never run into
> that problem.

Its been a while since I've had to use WP-Cache or tried to use it. It
very well may be better now, or my differences could have always been
related to heavy disk access anyways which made WP-Cache on top just
seem to slow down even more. I've found on most hardware sites I've
had to optimize for end up being IO-bound, not CPU bound, so in most
cases trying to keep things off disk IO doesn't hurt.

> > I believe there's some smaller optimizations that still may help. I
> > personally believe throwing all the files together into one giant
> > include would likely help.
>
> The only advantage to that over APC would be no stat calls to see if the
> file has changed. You can actually tell APC not to check if a file has
> changed, which means you have to restart it whenever you update a file,
> but we found that had little or no effect.
>
> I think a far larger benefit would come from simply dividing WP's files
> up more so not everything is loaded for every request. A lot of
> functions are used only for the backend, or only for RSS, or only on
> non-RSS pages, and being smarter about what code we include I think can
> have a big impact. This is different from on-demand loading.

This is actually a part of what Andy and I have been talking about
recently. The discussion came up over a year ago as well, but nothing
ever came of it.

-- 
--Robert Deaton
http://lushlab.com