[Zope] ZSQL Cacheing

[Rob Page]

> Do the queries  i.e.   sql.get_skin(username='default')  
> cache only for that given set of inputs? Or do they cache 
> regardless of the inputs? Because we have seen some evidence that the 
> result returned doesn't always change even when the username does and
it _should_ have
> to go look it up again.

IIRC from earlier investigations and presentations from Jim et al the
cacheing data structure is keyed on the rendered string of SQL that is
sent to the RDBMS.  There are probably some zany dynamic SQL queries
that could render the same query string for different input values.  If
the rendered string is different then the expected behavior is that the
cache would miss causing Zope to reissue the query to the RDBMS.

--Rob