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Date: Thu, 03 Apr 2008 08:39:28 +0200
From: Arjen van der Meijden <acmmailing@tweakers.net>
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To: users@activemq.apache.org
Subject: Re: Basic queue concept
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On 3-4-2008 7:47, Joel Poloney wrote:
> 1. I have a consumer in a while(1) { //consume } fashion. That would
> basically run forever. As I understand it, this is the way most web servers
> work (at the core, core level). In this model, I would have to make sure
> that the consumer was always running (perhaps do 3-way redundancy and have 3
> consumers doing this). My concern with this model is that if I implement
> this in PHP, I'm afraid of memory issues and so on. I don't necessarily
> trust a PHP script to run in a while(1) fashion forever.

I have this set-up, with four different consumers with varying load (two 
do more than two million entries per day, one only a few hundred and one 
a few ten thousand). I have seen no memory leak whatsoever from them.
The only major memory leakage from php I've seen recently was with 
SimpleXML, so if you intend to do XML-processing with those scripts, use 
DOM or expat.

Ironically, ActiveMQ leaks memory in my setup and therefore has a lower 
uptime than my php-consumers :X

> 2. I could somehow get the queue size and batch process these. Basically,
> get the queue size (say it was 200 entries), consume 200 messages and then
> the PHP script would end. Then you would have this script in a cronjob that
> runs every x amount of time.
> 
> Unfortunately, I have to implement this in PHP. So, I'm not really sure
> which way would be the proper way to go about doing this. If any one has any
> thoughts or comments, it would be greatly appreciated.

I would go with 1. But you may want to add some control-code to ensure 
you can easily and cleanly kill your scripts. In my code, I added a few 
signal handlers, so the consumer first finishes its most recent job and 
then dies. But than the fread-calls in the Stomp-implementation won't 
get interrupted. So I've a 'kill'-message for that situation, so my 
consumer dies as soon as its either blocked in fread waiting for a new 
message or right after its current job.

Best regards,

Arjen