[php-maint] Bug#631098: PHP Garbage Collection

[Bob Proulx]

Martin Meredith wrote:
> I've had a problem where somehow, I've managed to end up with
> approximately 1,000,000 session files on my server.

That is definitely a very large number of files all in one place!

> Due to the large amount of files, the current crontab to clear them
> was unable to deal with it (xargs would fail to take in the HUGE
> list of files).
>
> It seems that rather than using xargs (even with the limit), that
> using the -exec option of find might be a little bit more sane?

I realize that the cron script has already changed in later releases
but just the same this shouldn't have been a problem with the previous
version that used xargs.  Using xargs is an older but quite acceptable
way to deal with a very large list of filenames.  I think that there
was some different problem related to this that wasn't diagnosed.

In other words, while using 'find . -exec command {} +' is more
efficient than 'find . -print0 | xargs -0 command' they are both
equivalent in functionality.  And using 'find . -conditions -delete'
is even better for safety and efficiency the 'xargs -0' version is
still functionally correct.  Today it is best to use -delete since it
is newly available in find.  But before the -delete and the "{} +"
forms were available then the 'find . -print0 | xargs -0 ...' form was
the standard of excellence and will handle directories with millions
of files in it.

In yet other words, I feel certain that the actual problem was
something else and not the use of 'find . ... -print0 | xargs -0 ...'
there.  For example perhaps memory was so limited that the Linux
kernel out-of-memory killer (OOM Killer) came into place?  Just as an
example and not necessarily saying that was the specific problem you
hit.

Bob