Re: Core team statement on replication in PostgreSQL

Andrew Sullivan <ajs@commandprompt.com> writes:
> On Thu, May 29, 2008 at 12:05:18PM -0700, Robert Hodges wrote:
>> people are starting to get religion on this issue I would strongly
>> advocate a parallel effort to put in a change-set extraction API
>> that would allow construction of comprehensive master/slave
>> replication.  

> You know, I gave a talk in Ottawa just last week about how the last
> effort to develop a comprehensive API for replication failed.

Indeed, core's change of heart on this issue was largely driven by
Andrew's talk and subsequent discussion.  We had more or less been
waiting for the various external replication projects to tell us
what they wanted in this line, and it was only the realization that
no such thing was likely to happen that forced us to think seriously
about what could be done within the core project.

As I said originally, we have no expectation that the proposed features
will displace the existing replication projects for "high end"
replication problems ... and I'd characterize all of Robert's concerns
as "high end" problems.  We are happy to let those be solved outside
the core project.

About the only thing that would make me want to consider row-based
replication in core would be if we determine that read-only slave
queries are impractical atop a WAL-log-shipping implementation.
Which could happen; in fact I think that's the main risk of the
proposed development plan.  But I also think that the near-term
steps of the plan are worth doing anyway, for various other reasons,
and so we won't be out too much effort if the plan fails.
        regards, tom lane