[Pgpool-general] Replication Flawed?

[Tatsuo Ishii]

> On Thu, May 18, 2006 at 09:51:39AM +0900, Tatsuo Ishii wrote:
> > > > > I have run the same tests (and passed) using a JDBC based replication system, Sequoia (sequoia.continuent.org), which ensures replication consistency by ordering statements from all transactions based on ids assigned to them AFAIK.
> > > > 
> > > > Once I thought of such that method but I concluded that it will result
> > > > in performance loss because assigning "id" to each transactions itself
> > > > needs to kill concurrency of transactions.
> > > > 
> > > > If Sequoia overcomes the problem I worry about in some way, it will be
> > > > interesting. Let me check it.
> > > 
> > > Sequoia has the notion of statement queues; read-only statements can run
> > > in any queue, and be serviced by any database, but DML must run in a
> > > single queue and be serviced in order.
> > 
> > If so, I guess the DML performance of Sequoia would be unacceptably bad.
> 
> How would it be any worse than with Slony?

Don't know. I'm not familiar with Slony-I.

> And how else could you do it
> and ensure data consistency?

There could be many ways. One of them is table locking as I suggested.
--
Tatsuo Ishii
SRA OSS, Inc. Japan