Re: max_standby_delay considered harmful

Greg Stark <gsstark@mit.edu>

From: Greg Stark <gsstark@mit.edu>

To: Greg Smith <greg@2ndquadrant.com>

Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org, Bruce Momjian <bruce@momjian.us>, Robert Haas <robertmhaas@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, Josh Berkus <josh@agliodbs.com>

Date: 2010-05-09T16:47:51Z

Lists: pgsql-hackers

On Sun, May 9, 2010 at 4:00 AM, Greg Smith <greg@2ndquadrant.com> wrote:
>  The use cases are covered as best they can be without better support from
> expected future SR features like heartbeats and XID loopback.

For what it's worth I think deferring these extra complications is a
very useful exercise. I would like to see a system that doesn't depend
on them for basic functionality. In particular I would like to see a
system that can be useful using purely WAL log shipping without
streaming replication at all.

I'm a bit unclear how the boolean proposal would solve things though.
Surely if you set the boolean to recovery-wins then when using
streaming replication with any non-idle master virtually every query
would be cancelled immediately as every HOT cleanup would cause a
snapshot conflict with even short-lived queires in the slave.

-- 
greg