On 18 February 2016 at 20:35, Michael Paquier <michael.paqu...@gmail.com>

> On Thu, Feb 18, 2016 at 5:35 PM, Amit Langote
> <langote_amit...@lab.ntt.co.jp> wrote:
> > On 2016/02/18 16:38, Craig Ringer wrote:
> >> I should resurrect Abhijit's patch to allow the isolationtester to talk
> to
> >> multiple servers. We'll want that when we're doing tests like "assert
> that
> >> this change isn't visible on the replica before it becomes visible on
> the
> >> master". (Well, except we violate that one with our funky
> >> synchronous_commit implementation...)
> >
> > How much does (or does not) that overlap with the recovery test suite
> work
> > undertaken by Michael et al? I saw some talk of testing for patches in
> > works on the N synchronous standbys thread.
> This sounds like poll_query_until in PostgresNode.pm (already on HEAD)
> where the query used is something on pg_stat_replication for a given
> LSN to see if a standby has reached a given replay position.

No, it's quite different, though that's something handy to have that I've
emulated in the isolationtester using a plpgsql function.

The isolationtester changes in question allow isolationtester specs to run
different blocks against different hosts/ports/DBs.

That lets you  make assertions about replication behaviour. It was built
for BDR and I think we'll need something along those lines in core if/when
any kind of logical replication facilities land, for things like testing
failover slots, etc.

The patch is at:


and might be something it's worth having in core as we expand testing of
replication, failover, etc.

 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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