PG12
Steps to reproduce on 3 nodes cluster with quorum commit.
1. Cut off network on master with everything.
2. Pkill -9 PostgreSQL on each node.
3. Start PostgreSQL on each node.
What was strange?
I check every second pg_last_wal_replay_lsn() and pg_last_wal_receive_lsn().
All time it was the same.
For example last output before killing PostgreSQL:
2020-05-08 08:31:44,495 DEBUG: Last replayed LSN: 0/502E3D8
2020-05-08 08:31:44,497 DEBUG: Last received LSN: 0/502E3D8
After starting PostgreSQL I got this:
2020-05-08 08:31:55,324 DEBUG: Last replayed LSN: 0/502E3D8
2020-05-08 08:31:55,326 DEBUG: Last received LSN: 0/5000000
Why could it happen and is it expected behaviour?