Re: FDW-based dblink

On Thu, Aug 13, 2009 at 02:01:19PM +0300, Heikki Linnakangas wrote:
> Itagaki Takahiro wrote:
> > Present dblink is a thin wrapper of libpq, but some of my customers
> > want automatic transaction managements. Remote transactions are
> > committed with 2PC when the local transaction is committed.
> > To achieve it, I think we need on-commit trigger is needed,
> > but it is hard to implement with current infrastructure.
> > (That is one of the reason I proposed to merge dblink into core.)
>
> Quite aside from the requirement for on-commit trigger, how exactly
> would you use 2PC with the remote database? When would you issue PREPARE
> TRANSACTION, and when would COMMIT PREPARED?

For what it's worth, in DBI-Link, I've allowed some of this by letting
people pass commands like BEGIN, COMMIT and ROLLBACK through to the
remote side. However, it doesn't--can't, as far as I know--implement
the full 2PC.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com

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