Horton

Re: AW: Replication Testing- How to introduce a Lag

Laurenz Albe <laurenz.albe@cybertec.at>

View thread View on postgr.es
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: "Subramanian,Ramachandran" <ramachandran.subramanian@alte-leipziger.de>, "pgsql-novice@lists.postgresql.org" <pgsql-novice@lists.postgresql.org>
Date: 2026-03-25T06:04:14Z
Lists: pgsql-novice 
On Tue, 2026-03-24 at 17:01 +0000, Subramanian,Ramachandran wrote:
> My question is , can the difference in LSN from this query approximated
> to the amount of data that is yet to be transferred
> 
> select  pg_wal_lsn_diff(pg_current_wal_lsn(),replay_lsn) from pg_stat_replication

That query measures the replication lag in bytes, that *is* the amount of data.

Problem solved!

Yours,
Laurenz Albe