My apache processes are typically 18MB-20MB in size, with all but 500K to
1MB of that shared. We restart our servers in the middle of the nite as
part of planned maintenance, of course, but even before we did that,
and even after weeks of uptime, the percentages did not change.
We do not use Apache::Registry at all; everything is a pure handler. We
cache all data structures (lots of storable things) in the parent process
by thawing refs to the datastructures into package variables. We use no
globals, only a few package variables (4) that we access by fully
qualified package name, and they get reset on each request.
We use Apache::DBI and MySQL, and it works perfectly other than a few
segfaults that occur once in a while. Having all of the data structures
cached (and shared !) allows us to do some neat things without having to
rely solely on sql.
On Thu, 20 Apr 2000, Stas Bekman wrote:
> On Wed, 19 Apr 2000, Joshua Chamas wrote:
>
> > Stas Bekman wrote:
> > >
> > > Geez, I always forget something :(
> > >
> > > You are right. I forgot to mention that this was a scenario for the 23 Mb
> > > of unshared memory. I just wanted to give an example. Still somehow I'm
> > > almost sure that there are servers where even with sharing in place, the
> > > hypothetical scenario I've presented is quite possible.
> > >
> > > Anyway, it's just another patent for squeezing some more juice from your
> > > hardware without upgrading it.
> > >
> >
> > Your scenario would be more believable with 5M unshared, even
> > after doing ones best to share everything. This is pretty typical
> > when connecting to databases, as the database connections cannot
> > be shared, and especially DB's like Oracle take lots of RAM
> > per connection.
>
> Good idea. 5MB sounds closer to the real case than 10Mb. I'll make the
> correction. Thanks!!!
>
> > I'm not sure that your scenario is worthwhile if someone does
> > a good job preloading / sharing code across the forks, and
> > the difference will really be how much of the code gets dirty
> > while you run things, which can be neatly tuned with MaxRequests.
>
> Agree. But not everybody knows to do that well. So the presented idea
> might still find a good use at some web shops.
>
> > Interesting & novel approach though. I would bet that if people
> > went down this path, they would really end up on different machines
> > per web application, or even different web clusters per application ;)
>
> :)
>
>
> ______________________________________________________________________
> Stas Bekman | JAm_pH -- Just Another mod_perl Hacker
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