httpd-modules-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Danie Qian" <>
Subject Re: load data at server startup - is ap_hook_post_config() the right place?
Date Fri, 23 Mar 2007 19:24:10 GMT
----- Original Message ----- 
From: "David Wortham" <>
To: <>; "Danie Qian" <>
Sent: Friday, March 23, 2007 2:39 PM
Subject: Re: load data at server startup - is ap_hook_post_config() the 
right place?

> Daniel,
>    AFAIK, "mutex" refers to mutual exclusion.  It is commonly referred to
> in relation to multi-threading but can apply to an inter-process scheme
> too.  I would assume that only one thread of one (child) process can 
> access
> a given resource at a given time, but you should refer to the 
> documentation
> of any code you use for those specifics.  I'm sorry, but I don't have any
> personal experience with mutex and the APR libs.
>   Are you talking about adjusting your Apache child/thread setup for
> development or are you targeting your module to only Apache installations
> with specific configuration (i.e. single-thread mode)?
> If you are worried about the size of a child process' 
> server_config_struct,
> you could just program it to take a lot of room in the 
> server_config_struct
> and recommend that Apache be configured for only one child-process.  I 
> would
> recommend against it, but it doesn't seem like a terrible idea.  There 
> will
> probably be significant performance hits on certain 
> OSes/Apache-deployments
> (*NIX) and less on others (likely WinNT since I believe it defaults to a
> single-child process with a large thread-count).
>   Also, what are you using this giant list of URIs for?  There may be a
> more efficient way of distributing the processing load (and, therefore,
> speeding up the overall Apache response time).  If I read your first post 
> to
> this list correctly, you are using a table (as in apr_table_*, a DB table,
> or other?) with a large number of URLs.  You aren't walking through a
> sequential list of URLs in apr_tables are you?  Are the "URI"s you're
> storing full URIs, domain names, or MXs?  Perhaps you could use some help
> with your overall design of the module (or maybe there's an existing 
> module
> that does what you want).

Hi Dave,

To be more meaningful about what I am talking about, here is our setup: We 
have around 5 thousand sites running on a few web-farmed locations. Each 
location has about 10~20 linux apache servers running behind a load 
balancer. Every apache usually has 40~50 child processes running to serve 
the amount traffic. Internally every site is maintained as one of our 
products with all its operation information stored in mysql databases. With 
the information from one of the tables we can decide where the site folder 
is by looking at the site name and some other fields associated with the 
site. What I am thinking to do with the module is to load all the relevant 
fields into apache memory space upon apache startup and let every request 
look up from that chunk of memory for better performance. so as u can see we 
are nailed a setup of multiple processes and probably single thread mode in 


View raw message