Re: 2-phase commit

Mike Mascari wrote:
> Bruce Momjian wrote:
> > I haven't seen any comment on this email.
> > 
> > From our previous discussion of 2-phase commit, there was concern that
> > the failure modes of 2-phase commit were not solvable.  However, I think
> > multi-master replication is going to have similar non-solvable failure
> > modes, yet people still want multi-master replication.
> > 
> > We have had several requests for 2-phase commit in the past month.  I
> > think we should encourage the Japanese group to continue on their
> > 2-phase commit patch to be included in 7.5.  Yes, it will have
> > non-solvable failure modes, but let's discuss them and find an
> > appropriate way to deal with the failures.
> 
> FWIW, Oracle 8's manual for the recovery of a distributed tx where the
> coordinator never comes back on line is:
> 
> https://www.ifi.uni-klu.ac.at/Public/Documentation/oracle/product/8.0.3/doc/server803/A54643_01/ch_intro.htm#7783
> 
> "If a database must be recovered to a point in the past, Oracle's
> recovery facilities allow database administrators at other sites to
> return their databases to the earlier point in time also. This ensures
> that the global database remains consistent."
> 
> So it seems, for Oracle 8 at least, PITR is the method of recovery for
> cohorts after unrecoverable coordinator failure.

Yep, I assume PITR would be the solution for most failure cases --- very
ugly of course.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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