[pgpool-general: 8550] Re: Issues taking a node out of a cluster

[Tatsuo Ishii]

> Ok, but how do I then change the topology of the cluster without downtime?

There's no way to change the "topology" of the cluster without
restarting pgpool.

> Removing or adding a node does not require any downtime from the
> perspective of Postgresql (as long as the primary stays online, you'll need
> a switchover otherwise). Looking at the documentation, pgpool only allows
> adding backends without restart, not removing or updating.
> 
> Wouldn't it be possible for pgpool to use the backend_application_name as
> identifier, or perhaps add a new configuration option to assign a unique
> identifier to a backend? It could then use this identifier to share status
> information about backends between nodes in the cluster.

Can you elaborate the motivation behind this? It seems you just want
to stop PostgreSQL node 1 and then rename PostgreSQL node 2 to node
1. I don't see benefit from this for admins/users except avoiding the
node 1 "whole" from the configuration file.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
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