On Fri, 2002-12-13 at 13:36, Jan Wieck wrote:
> But you cannot use the result of such a SELECT to update anything. So
> you can only phase out complete read only transaction to the slaves.
> Requires support from the application since the load balancing system
> cannot know automatically what will be a read only transaction and what
> not.
Interesting -- SQL contains the concept of "read only" and "read write"
transactions (the default is RW). If we implemented that (which
shouldn't be too difficult[1]), it might make differentiating between
classes of transactions a little easier. Client applications would still
need to be modified, but not nearly as much.
Does this sound like it's worth doing?
[1] -- AFAICS, the only tricky implementation detail is deciding exactly
which database operations are "writes". Does nextval() count, for
example?
Cheers,
Neil
--
Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC