Re: Null value returned by function pg_last_wal_receive_lsn() inLogical Replication
Hi Pavan ,
Please try below query , this should give you retention lag bytes in case of logical replication .
slot_name, database, active,
pg_xlog_location_diff(pg_current_xlog_insert_location(), restart_lsn) AS retained_bytes
From: pavan95 <[hidden email]> Sent: Tuesday, October 9, 2018 11:29 AM To:[hidden email] Subject: Re: Null value returned by function pg_last_wal_receive_lsn() inLogical Replication
I configured Logical Replication in Postgres 10.5 using 2 nodes(Publisher
and Subscriber). I'm in my way to find lag in logical replication.
From the documentation I found that, pg_current_wal_lsn() on the publisher
and pg_last_wal_receive_lsn() on the subscriber helps us to find the lag in
which the subscriber is falling behind.
But, the function pg_last_wal_receive_lsn() is continuously returning NULL
value. In fact, all the Recovery Information
are returning null.
But according to documentation, the above 3 functions will return NULL only
if streaming replication is disabled or if it has not yet started. But in my
case, the logical replication is working fine. So I wanted to know if I
could get a value by enabling any settings recommended.
Also, is there a query to find the lag in bytes between publisher and