On Mon, 6 Nov 2000, Differentiated Software Solutions Pvt. Ltd wrote:
> We want to share a variable across different httpd processes.
> Our requirement is as follows :
>
> 1. We want to define one variable (which is a large hash).
> 2. Every httpd should be able to access this variable (read-only).
> 3. Periodically (every hour) we would like to have another mod_perl program to
>refresh/recreate this large hash with new values
> 4. After this, we want the new values in the hash to be available across httpds
If that's all you want to do, I would stay away from the notoriously slow
and sometimes tricky IPC modules. My dirt simple approach is to put the
data in a file and then read it into each httpd. (No point in trying to
load it before forking if you're going to refresh it in an hour
anyway.) You can use Storable for your data format, which is compact and
fast. To check for an update, just stat the file and reload the data if
it has a newer mtime. If you don't like doing the stat every time, put a
counter in a global variable and just stat once every 10 requests or
something, like Apache::SizeLimit does. If your data is too big to pull
into memory, you can use a dbm file instead.
- Perrin
