Cache activity for larger catalog
Hi Im using ubercart with a 6000+ product catalog I am wondering how the cache-ing works here is the scenario

* only basic modules installed (uc- events - devel)
* dedicated lamp server
* we have been moving products between categories to fine tune (which presumably clears cache for that page)
* when going to a catalog page it usually takes 60-90 seconds to return the page results
scenario 1
* main slow downs are (according to devel module) pager query
25219.44 1 pager_query i.e. 25 seconds
56321.81 1 pager_query and 56 seconds
and a few other ones that were over 5ms

* when going to page 2 (pagination)
57291.01 1 pager_query

* when I go a page the next time ( a previously visited catalog pg) it loads much faster ( 5 or 6 seconds) with cache_get coming in at 11ms - so obviously the cache-ing works for (auth and anonymous) users

So that is the scenario... here is the questions
1) Does the cache clear it self every x hours/days
1a) how to avoid this?

2) Is there a way to pre build the cache other than visiting every page manually
2a) If a site admin adds/moves a product how can we rebuild cache for that page, other than manually visiting it

3) Is there any other cacheing going on (local computer/isp/etc)(im guessing yes but nothing substantial relating to the issue in question)

4) When drupal/uc builds a catalog page from a http request does it build it out for all products (taxonomy children) in catalog (6000) or in that section (1000) or in a subsection (100)
4a) if you go to page 2 (pagination) is that then cached (i dont think it is as per scenario above)
4b) would the number of products per page (currently 10 in basic rows) make a difference to non cache load time and cached load time?
4c) I will eventually turn on the catalog grid would this be another performance hit?

5) Would server hardware upgrade help additional RAM / faster prosc. / allocate more mem to php? ( i think the server is a mid range p4 with 512 or 1gb ram)

6)what should i focus in on to address the core problem of long load times for non cached pages due to pager_query time to complete.

I realize this is a bit convoluted... I can include screen caps if req.
any insight would be greatly appreciated...uber-thanks in advance...