Post the setup of streaming replication –MASTER and one SLAVE in PostgreSQL 12 , the pg_wal in both MASTER/SLAVE are - filling up.
Do you have any replication slots on the replica? When you created the replica, you were supposed to exclude the directory pg_replslot. If you didn't the replica might have "inherited" slots it should not have.
No I haven’t created any replication slots on the replica, but its keep filling the logs in pg_wal? So does it mean it can go anywhere without a slot?
My MASTER is in archive log mode and SLAVE in no archive log mode.