MS RFC 22: Data adapter support

[Stephen Woodbridge]

Tamas Szekeres wrote:
> Folks,
> 
> According to the mapserver 5.0 development plan
> http://mapserver.gis.umn.edu/development/release_plans/mapserver_5_0
> we have planned to implement feature cache support for long running
> processes and query processing. This support will increase the
> performance of the long running processes by maintaining the features
> from a previous query in an internal memory cache.
> 
> The first step to implement this feature is to provide a framework to
> modify the behaviour of the  existing providers in an unified manner.
> The changes described in RFC 22 will address this issue.
> 
> http://mapserver.gis.umn.edu/development/rfc/ms-rfc-22
> 
> Any comments and suggestions will be appreciated.
> 
> Best Regards,
> 
> Tamas

Tamas,

This is a great writeup. It is very clear and easy to follow.

Have you thought about the caching mechanism at all? I would like to 
suggest that you look at memcached. This is a very simple memory based 
caching mechanism that is key=value driven and uses a least recently 
used flushing along with other methods of expiring cache items. You can 
open a socket connection to a pool of memcached servers, and the api 
handles the rest. We you md5 digest hashes of the request for the keys 
which works very nicely with complex requests like xml, perl structures, 
SQL queries etc.

This could be configured to get from the cache or make the mapserver 
query and store the results to the cache.

There are a lot of large sites using this to cache sessions and/or 
database queries with great results, there is an active list for support 
and fixes and it is an OpenSource project.

Anyway, I'm associated with them, but please look it over if you are not 
already familiar with it.

-Steve W.