I have a linux system with apache httpd and PHP which is loaded using
LoadModule php5_module /usr/lib/apache2/modules/libphp5.so.
I've enabled the mod_status module of apache and I see a particular thread which is stuck doing something since yesterday. I also confirm this by doing
ps -axu | grep apache which among the many threads it gives me that particular stuck thread:
www-data 5636 0.0 0.1 423556 23560 ? S XXXXX 0:04 /usr/sbin/apache2 -k start
Note that XXXXX is something like Jan02 which is yesterday. Also, the pid (5636) matches the pid of the stuck thread I see in the mod_status page of apache.
My question is: how can I do a thread dump or something similar in order to see where exactly in the PHP code this thing is stuck? Maybe it's waiting for something (i/o, network, db) but I don't know what.
In the java world I'd do a
kill -3 pid and get a nice readable thread dump which would clearlly show me where exactly that particular thread is stuck at. Is there a similar technique for the php land?