From: | Neil Conway <neilc(at)samurai(dot)com> |
---|---|
To: | Jan Wieck <JanWieck(at)Yahoo(dot)com> |
Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, shridhar_daithankar(at)persistent(dot)co(dot)in, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Big 7.4 items |
Date: | 2002-12-13 23:38:33 |
Message-ID: | 1039822713.1397.35.camel@tokyo |
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Lists: | pgsql-hackers |
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(at)samurai(dot)com> || PGP Key ID: DB3C29FC
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