Re: PECL/memcached segfaults

Well, apparently, I am not the only one.

http://pecl.php.net/bugs/bug.php?id=17382

Brian.
--------
http://brian.moonspot.net/

On 5/6/10 1:09 AM, Brian Moon wrote:
> I was finally able to reproduce the cause on my dev server. The
> segfaults were caused by the process exceeding its open file limit. This
> explains why only one data center had segfaults (the busier one) and the
> other only saw increasing connections to memcached.
>
> On a dev server, running the worker MPM and mod_php, I configured the
> server with:
>
> StartServers 2
> MinSpareThreads 20
> MaxSpareThreads 20
> ThreadsPerChild 10
> MaxClients 20
> MaxRequestsPerChild 0
>
> This creates 2 Apache processes, each with 10 threads for a total of 20
> children.
>
> I am using persistent connections when creating the memcached connections.
>
> The memcached connection count grows and grows and grows until the
> process hits 1024 open files and is killed by the kernel.
>
> I did write the persistent string being sent to the object constructor
> out to the php error log to ensure we were not sending a unique string
> each time. We are not. At most there should be two connections per
> child/process (not sure how the persistence is handled for threads).
> pecl/memcache creates them per child (thread).
>
> I turned off the persistence and things work as they should. The
> connection count does not grow.
>
> So, next I turned off worker thinking this was a threading issue. But,
> the problem persisted.
>
> In the end, I was able to reproduce the issue with a simple script. Here
> is the script and output: http://pastebin.com/40vzVM7D There is a run
> with pecl/memcache there as well to show the difference in behavior.
>
> Tested platforms:
>
> Gentoo Linux
> PHP/5.2.13
> libmemcached/0.38 thru 0.40
> pecl-memcached/1.0.0 thru 1.0.2
>
> Mac - Darwin Kernel Version 10.3.0
> PHP 5.3.1
> libmemcached/0.40
> pecl-memcached/1.0.2
>