Re: TDS question

• To: Luca Cinquini <luca@xxxxxxxx>
• Subject: Re: TDS question
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Wed, 20 Sep 2006 13:11:27 -0600

Luca Cinquini wrote:

Hi John,

is there any documentation that explains the TDS caching mechanism ? For example, are the THREDDS catalogs re-generated each time Tomcat is started, or are they serialized somewhere ?

on startup, TDS reads in all static catalogs (which can be thought of as configuration files) and 
caches them. If the catalog has an "expires" attribute, it will reread them upon 
expiration. You can force re-reading by using an expires date before todays date. You can also 
force rereading the catalogs through a "reinit" command, if you have https enabled and 
are authorized.

dynamic catalogs are generated dynamically. We are considering caching them for 
some amount of time, but i dont think we've implemented yet (Im cc'ing ethan to 
double check that).

I noticed that the aggregation files are indeed cached in /content/ thredds/cache (or cacheAged).

aggregation has another set of caching going on (still evolving), and 
/content/thredds/cache is one of the default places it uses (can be changed). 
these arent catalogs, but NcML agg elements, but they are integrated into the 
TDS.

theres some sketchy docs at:

http://motherlode.ucar.edu:8080/thredds/docs/internal/Caching.htm

FYI I am sending you a diagram that shows how I enabled authorized TDS access from the CDP. We are still in prototype mode, but the idea is to start using the TDS as a FileServer, an OPeNDAP server and whatever it will do in the future.

I really want to catch up with you on this, but im swamped at the moment, so it 
will have to be after im back from vacation (Oct 3). If its helpful, we can 
talk on the phone this week, however.

thanks, Luca