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Hi Pavan ,
Please try below query , this should give you retention lag bytes in case of logical replication .
SELECT
slot_name, database, active,
pg_xlog_location_diff(pg_current_xlog_insert_location(), restart_lsn) AS retained_bytes
FROM pg_replication_slots;
Thanks ,
Soumitra
From: pavan95 <pavan.postgresdba@xxxxxxxxx>
Sent: Tuesday, October 9, 2018 11:29 AM To: pgsql-admin@xxxxxxxxxxxxxx Subject: Re: Null value returned by function pg_last_wal_receive_lsn() inLogical Replication Hi Community,
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 Functions(pg_last_wal_receive_lsn(),pg_last_wal_replay_lsn(),pg_last_xact_replay_timestamp()) are returning null. >From the Subscriber: subscriber_db=# select pg_last_wal_receive_lsn(); pg_last_wal_receive_lsn ------------------------- (1 row) 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 subscriber? Thanks in Advance. -- Sent from: http://www.postgresql-archive.org/PostgreSQL-admin-f2076596.html |
