Re: Reducing bandwidth usage of database replication

On Thu, 3 Nov 2022 at 15:28, Ben Chobot <bench(at)silentmedia(dot)com> wrote:

> I want to use the postgres-native logical replication to have multiple clients receive and send data to a central database.
> Real-time is far less important than network usage, and with my current test setup it appears both instances communicate frequently if a subscription is active, even if nothing is happening.
>
> Is there a good way to reduce data usage, for example by limiting the amount of keep-alive messages? One database will likely be idle most of the time.

Keep-alive messages are the largest concern on an otherwise quiet link.

Probably makes sense to let the connection time out, then set a large
wal_retrieve_retry_interval, so it doesn't immediately reconnect.

> It sounds like you are trying to use logical replication to give yourself a multi-master database setup, and that you've squeezed as much optimization as you can from logical replication and found it to be unworkable. If that's a fair assessment, you might look into something like bucardo instead. I haven't done the network comparison but it is a different solution that might meet your goals.

The overhead of Bucardo has been measured as being more than 3x that
of logical replication.

--
Simon Riggs http://www.EnterpriseDB.com/