Re: Database Caching

On Sun, Aug 25, 2002 at 09:35:24PM -0400, J. R. Nield wrote:
> I'm not sure about query result caching or 'relation caching', since the
> first would seem to run into problems with concurrent updates, and the
> second is sort-of what the buffer cache does.
>
> Query plan caching sounds like a really good idea though. Neil Conway's
> PREPARE patch already does this for an individual backend. Do you think
> it would be hard to make it use shared memory, and check if a query has
> already been prepared by another backend? Maybe it could use something
> like a whitespace insensitive checksum for a shared hash key.

The original version of query plan cache allows exactly this. But
after some discussion the shared memory usage in qcache was remove.

I think better and more robus solution is store cached planns in
backend memory and allows to run backend as persistent (means not
startup/stop for each client connection).

Karel

--
Karel Zak <zakkr(at)zf(dot)jcu(dot)cz>
http://home.zf.jcu.cz/~zakkr/

C, PostgreSQL, PHP, WWW, http://docs.linux.cz, http://mape.jcu.cz