Re: the cause of the cause, our speculation based on an occasional error
message had to do with the process running out of the "special" unix
file handles. The processes open and close lots of files (and yes, we
are explicitly closing files) and it seems for no rhyme or reason after
the processes run for a while the handles never seemed to really get
freed and would stack up and house the daemons. We could never
replicated in a lab, it would just happen from time to time and the
errors were things we could not explicitly control from PHP. (Note that
we found all this in the 4.x CLI and have not re-tested in the PHP 5.x
CLI. Our solution works great so why change it? Plus, if there are any
strange behaviors in the CLI they won't get exploited by dying and
re-spawning.)
So, what I mean re: "eternal" is that we can give our base daemon class
an optional "lifetime" count (e.g., the number of times the daemon
should perform its core processing before suicide) and an optional
"eternal" command. Since we have a common way to spawn our daemons this
eternal command is usually just the current script name plus some
specific command-line parameters. Once the daemon reaches its lifetime,
it requests its death, optionally re-spawning itself if there is an
eternal command given. This command can be kicked off via your method of
choice, e.g. pcntl_exec, exec, etc.
No real magic here, just a simple method to insure we can have clean
process spaces. :-)
-- AD
-----Original Message-----
From: Ron Korving [mailto:r.korving@xit.nl]
Sent: Thursday, October 06, 2005 7:48 AM
To: internals@lists.php.net
Subject: Re: [PHP-DEV] CLI in PHP6
FWIW
A lot :) Thanks for the response. It's good to see it is possible.
However, a process running for a long time (yes, even on
Linux) will also just "die" for no reason. We have a few hints as to
what causes the deaths but don't know what causes the cause. To solve
the problem we created a daemon class that has a lifetime and can make
itself "eternal" if desired. The net effect is a stable daemon(s).
Could you get into a little more detail? I don't quite understand what
you
mean by this daemon class that can make itself "eternal" and how this
can
turn the situation stable.
Thanks,
Ron
""J. Allen Dove"" adove@booyahnetworks.com schreef in bericht
news:4E0C5C8E5F8C994F90134920DD66E93F011292EE@pearl.hq.booyahnetworks.co
m...
FWIW, we have been running a number of very high-volume PHP CLI daemons
for the last 18-20 months with great success. That is not to say it
wasn't a challenge to get them as "stable" as a C++ daemon but we have.
PHP 4.x CLI seemed to have a mem leak somewhere, PHP 5.x seems to have
resolved that. However, a process running for a long time (yes, even on
Linux) will also just "die" for no reason. We have a few hints as to
what causes the deaths but don't know what causes the cause. To solve
the problem we created a daemon class that has a lifetime and can make
itself "eternal" if desired. The net effect is a stable daemon(s).
We currently process 65-70MM transactions a day with our PHP-based
daemons. We chose to try using PHP to share business logic and it paid
off.
-- Allen
-----Original Message-----
From: Ron Korving [mailto:r.korving@xit.nl]
Sent: Thursday, October 06, 2005 2:49 AM
To: internals@lists.php.net
Subject: [PHP-DEV] CLI in PHP6
Hi,
There was once (can't remember when exactly, so it must be a long time
ago)
here on PHP CLI scripts in which it came forward that one should not
rely on
such a script to run forever. And it's true; the scripts sometimes
magically
and suddenly die. Now I have no clue where this instability (for lack of
a
better word) comes from, but could it be possible for this to be
resolved
for PHP6 so that PHP becomes an extremely viable solution for CLI daemon
scripts?
Thanks,
Ron Korving