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. Butafter some discussion the shared memory usage in
qcachewas remove.
 
I think better and more robus solution is store cached planns inbackend memory and allows to run backend as persistent
(meansnotstartup/stop for each client connection).
 
   Karel

-- Karel Zak  <zakkr@zf.jcu.cz>http://home.zf.jcu.cz/~zakkr/C, PostgreSQL, PHP, WWW, http://docs.linux.cz,
http://mape.jcu.cz