On Wed, Jan 11, 2012 at 4:33 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> BTW ... it occurs to me to ask whether we really have a solid use-case
> for having listeners attached to slave servers. I have personally never
> seen an application for LISTEN/NOTIFY in which the listeners were
> entirely read-only. Even if there are one or two cases out there, it's
> not clear to me that supporting it is worth the extra complexity that
> seems to be needed.
The idea is to support external caches that re-read the data when it changes.
If we can do that from the standby then we offload from the master.
Yes, there are other applications for LISTEN/NOTIFY and we wouldn't be
able to support them all with this.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
