----- Original Message -----
From: "David Wortham" <[EMAIL PROTECTED]>
To: <[email protected]>; "Danie Qian" <[EMAIL PROTECTED]>
Sent: Friday, March 23, 2007 11:34 AM
Subject: Re: load data at server startup - is ap_hook_post_config() the
right place?
Daniel,
I believe (I am a module programmer with only novice Apache API
experience) that there are quite a few server configs created.
From my experiments with my module, there appear to be at least two
running all the time (what appears to be a "global" server config and one
server config for every virtualhost defined in httpd.conf and other config
files).
Also, I would guess that each child process has their own copy of the
server configs.
I believe this because every time a server_config_merge function is
called,
the server config is edited.
The server_config_merge function is run at server startup (based on
httpd.conf settings) and again at the beginning of a request (when
.htaccess
files are parsed... although I am not sure why).
AFAIK, every time a "variable" in the parent process is written to by a
child process, the child process is given a copy of the parent's variable
and only that copy (in the child process) is edited.
By that logic, I would think that not only do you potentially get one
server_config struct per (child process which writes to the server
config),
but each server_config_struct is independently modified by each child
process (on potentially different).
Maybe this page can shed some light on your questions:
http://www.fmc-modeling.org/projects/apache/html/3_3Extending_Apache.html
Regards,
Dave
--
David Wortham
Senior Web Applications Developer
Unspam Technologies, Inc.
1901 Prospector Dr. #30
Park City, UT 84060
(435) 513-0672
On 3/22/07, Danie Qian <[EMAIL PROTECTED]> wrote:
----- Original Message -----
From: "Dumindu Perera" <[EMAIL PROTECTED]>
To: <[email protected]>; "Danie Qian"
<[EMAIL PROTECTED]>
Sent: Thursday, March 22, 2007 1:18 PM
Subject: Re: load data at server startup - is ap_hook_post_config() the
right place?
Thanks for replying. Does every child process has one copy of the server
config or is there only one copy in the whole server memory space? I dont
want every child to have a copy as the config data is quite big in my
case.
Best Regards,
Daniel
Hi Dave,
I think you are right after piecing together all the information I gathered
from various places. As soon as a child process modify the data in the
server config created by the parent server, the child gets a copy of it.
This is ok if the server config is only a few httpd.conf directives but in
my case it would be very inefficient as the table to be put in server config
can grow to a few hundred Kilobytes. At this point child processes arent
required to dynamically change anything in the server config but I dont feel
comfortable to put in it being aware of the above fact.
Someone in the forum mentioned about mutex for this situaction. Now i have
one question: mutex is a multithread thing but if I run apache in
single-thread mode like prefork is it still the best solution?
Thanks,
Daniel
