Re: (ITS#6152) proxycache enhancements

[masarati@aero.polimi.it]

I wonder, in the spirit of further improving pcache:

- support compare, in case a cached query has the entry to be compared,
and the asserted attr is in the corresponding attrset?

- exploit modifications to invalidate queries whose results are altered? 
It'd be easy for deletes (check if present, and eventually remove the
entry).  An easy shortcut for modify/rename would be to just invalidate
queries affecting the modified entry (I'd prefer this to mimic
modifications to local data, which would also guarantee that remote server
ACLs have been applied).  Adds would be a little bit tricky (try all
cached queries on the new entry (base, scope, filter; in case of match,
invalidate them, so that the remote server can apply ACLs).

This may be a moot point, as usually cached proxies are essentially
read-only, but in case...

p.