> On Nov 12, 2018, at 10:28 PM, Andrey Zhidenkov <andrey.zhidenkov@xxxxxxxxx> wrote: > > We have a few database clusters (1 master, 2 hot standbys) with > hot_standby_feedback setting on. But I am constantly seeing query > conflicts on standbys because dead rows on the masters are deleted by > VACUUM. Usually I notice it shortly after VACUUM ends, because the > replication lag on replicas is starting to increase. > > vacuum_defer_cleanup_age = 0. PostgreSQL version is 9.5.13. Cluster > load is about 1500 transactions per second. > > Any ideas? > > - > With the best regards, Andrey Zhidenkov > Are these streaming replicas? The wal_streaming process on the master should show the xmin of the replicas; you can check the value from pg_stat_activity to make sure the feedback is occurring. Are the replicas disconnecting from the replication stream? As the would mean the xmin from the replica would no longer be in play.
