Re: Again, sorry, caching, (Tom What do you think: function

On Tue, 2002-03-19 at 07:46, mlw wrote:
[snip]

> Right now, the function manager can only return one value, or one set of values
> for a column. It should be possible, but require a lot of research, to enable
> the function manager to return a set of rows. If we could get that working, it
> could be fairly trivial to implement a cache as a contrib project. It would
> work something like this:
>
> select querycache("select * from mytable where foo='bar') ;

Interesting concept...but how would you know when the cache has become
dirty? That would give you a set of rows...but I don't understand what
would let you know your result set is invalid?

Perhaps: select querycache( foobar_event, "select * from my table where
foo='bar'" ) ; would automatically create a listen for you??

>
> This does two things that I would like to see: The ability to cache subselects
> independent of the full query. The ability to control which queries get cached.
>
> If we can get this row functionality in the function manager for 7.3, we could
> then implement MANY MANY enterprise level functionalities. Remote queries,
> query caching, external tables, etc. as contrib projects rather than full blown
> modifications to PostgreSQL.

Correct me if I'm wrong, but this concept would also be applicable to
some clustering/distributed query (that what you meant by remote
queries) needs too?

Greg