Shows the status of BDR replication slots. Output with the verbose flag gives details such as is slot active, replication state (disconnected, streaming, catchup), and approximate lag.
Symbol
Meaning
*
ok
~
warning (lag > 10M)
!
critical (lag > 100M OR slot is 'inactive' OR 'disconnected')
x
down / unreachable
-
n/a
In matrix view, sometimes byte lag is shown in parentheses. It is maxOf(WriteLag, FlushLag, ReplayLag, SentLag).
In this example, there is a 3 node cluster, bdr-a1 and bdr-c1 are up, bdr-b1 is down.
Or in Verbose mode:
Show replication slots with a recently restarted node
In this example, there is a 3 node cluster, bdr-b1 was down and it has just been restarted.
Or in Verbose mode:
Show replication slots with all nodes working correctly
In this example, there is a 3 node cluster with all nodes are up and in 'streaming' state.
Or in Verbose mode:
Show replication slots in a multi-node cluster
In this example, there is a 4 node cluster, with a witness node, a subscriber-only node, and two logical standbys. bdr-a1 and bdr-b1 are up and in 'streaming' state. bdr-a1 is replicating to logical-standby-a1 and bdr-b1 is replicating to logical-standby-b1. bdr-a1 is also replicating to subscriber-only-c1.
Note:
Data for a logical standby is only sent by one source node. No other nodes receive replication changes from the logical standby.
Subscriber-only node subscribes to replication changes from other nodes in the cluster, but no other nodes receive replication changes from it