Mod_wsgi daemon mode, separation of the WSGIApplicationGroup interpreter and Python

Question

I have Apache with two virtual hosts, each of which has a Django site connected using mod_wsgi, daemon mode, for example:

<VirtualHost 123.123.123.123:80> WSGIDaemonProcess a.com user=x group=x processes=5 threads=1 WSGIProcessGroup a.com WSGIApplicationGroup %{GLOBAL} </VirtualHost> <VirtualHost 123.123.123.123:80> WSGIDaemonProcess b.com user=x group=x processes=5 threads=1 WSGIProcessGroup b.com WSGIApplicationGroup %{GLOBAL} </VirtualHost> 

I am using WSGIApplicationGroup %{GLOBAL} due to a known issue with Xapian .

Now, if I understand what is going on behind the scenes, mod_wsgi starts 5 daemon processes for each of my sites. I see this in the Apache log:

 [info] mod_wsgi (pid=8106): Attach interpreter ''. [info] mod_wsgi (pid=8106): Adding '.../lib/python2.5/site-packages' to path. [info] mod_wsgi (pid=8106): Enable monitor thread in process 'a.com'. [info] mod_wsgi (pid=8106): Enable deadlock thread in process 'a.com'. [info] mod_wsgi (pid=8107): Attach interpreter ''. [info] mod_wsgi (pid=8107): Adding '.../lib/python2.5/site-packages' to path. [info] mod_wsgi (pid=8107): Enable monitor thread in process 'a.com'. [info] mod_wsgi (pid=8107): Enable deadlock thread in process 'a.com'. ... 

What I don’t understand is the "Attach interpreter ''" lines that indicate that all these processes have the same Python interpreter or if there is one interpreter for each process. (By the way, I understand that the empty interpreter name '' is caused by passing %{GLOBAL} to WSGIApplicationGroup ).

I tried to check if sys.path entries were cumulated in subsequent processes, but they didn’t, which may indicate that there is a separate Python interpreter for each of the 5 daemon processes ... but I don’t quite understand all these things, so I ask here.

Answer 1

The meaning of "pid" is different. They are in different processes.