Hi, As the 7.4 beta rolls on, I thought now would be a good time to start talking about the future.
I have a potential need in the future for distributed transactions (XA). To get that from Postgres, I'd need two-phase commit, I think. There is someone working on such a project (<http://snaga.org/pgsql/>), but last time it was discussed here, it received a rather lukewarm reception (see, e.g., the thread starting at <http://archives.postgresql.org/pgsql-hackers/2003-06/msg00752.php>). While at OSCON, I had a discussion with Joe Conway, Bruce Momjian, and Greg Sabino Mullane about 2PC. Various people expressed various opinions on the topic, but I think we agreed on the following. The relevant folks can correct me if I'm wrong: Two-phase commit has theoretical problems, but it is implemented in several "enterprise" RDBMS. 2PC is something needed by certain kinds of clients (especially those with transaction managers), so if PostgreSQL doesn't have it, PostgreSQL just won't get supported in that arena. Someone is already working on 2PC, but may feel unwanted due to the reactions last heard on the topic, and may not continue working unless he gets some support. What is a necessary condition for such support is to get some idea of what compromises 2PC might impose, and thereafter to try to determine which such compromises, if any, are acceptable ones. I think the idea here is that, while in most cases a "pretty-good" implementation of a desirable feature might get included in the source on the grounds that it can always be improved upon later, something like 2PC has the potential to do great harm to an otherwise reliable transaction manager. So the arguments about what to do need to be aired in advance. I (perhaps foolishly) volunteered to undertake to collect the arguments in various directions, on the grounds that I can contribute no code, but have skin made of asbestos. I thought I'd try to collect some information about what people think the problems and potentially acceptable compromises are, to see if there is some way to understand what can and cannot be contemplated for 2PC. I'll include in any such outline the remarks found in the -hackers thread referenced above. Any objections? A -- ---- Andrew Sullivan 204-4141 Yonge Street Liberty RMS Toronto, Ontario Canada <[EMAIL PROTECTED]> M2P 2A8 +1 416 646 3304 x110 ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
