Re: Core team statement on replication in PostgreSQL

Simon Riggs <simon@2ndquadrant.com> writes:
> On Fri, 2008-05-30 at 12:31 +0530, Gurjeet Singh wrote:
>> On Fri, May 30, 2008 at 10:40 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> But since you mention it: one of the plausible answers for fixing the
>>> vacuum problem for read-only slaves is to have the slaves push an xmin
>>> back upstream to the master to prevent premature vacuuming.
>>
>> I think it would be best to not make the slave interfere with the
>> master's operations; that's only going to increase the operational
>> complexity of such a solution.

> We ruled that out as the-only-solution a while back. It does have the
> beauty of simplicity, so it may exist as an option or possibly the only
> way, for 8.4.

Yeah.  The point is that it's fairly clear that we could make that work.
A solution that doesn't impact the master at all would be nicer, but
it's not at all clear to me that one is possible, unless we abandon
WAL-shipping as the base technology.
        regards, tom lane