SQL Distributed Availability Group (DAG) Health Check

 To check SQL DAG health with Query

SELECT 

       ag.name AS 'AG Name', 

       ag.is_distributed, 

       ar.replica_server_name AS 'AG', 

       dbs.name AS 'Database',

   ars.role_desc, 

drs.synchronization_health_desc, 

drs.log_send_queue_size, 

drs.log_send_rate, 

drs.redo_queue_size, 

drs.redo_rate,

drs.suspend_reason_desc,

drs.last_sent_time,

drs.last_received_time,

drs.last_hardened_time,

drs.last_redone_time,

drs.last_commit_time,

drs.secondary_lag_seconds

FROM sys.databases dbs 

INNER JOIN sys.dm_hadr_database_replica_states drs 

   ON dbs.database_id = drs.database_id

INNER JOIN sys.availability_groups ag 

   ON drs.group_id = ag.group_id

INNER JOIN sys.dm_hadr_availability_replica_states ars 

   ON ars.replica_id = drs.replica_id

INNER JOIN sys.availability_replicas ar 

   ON ar.replica_id =  ars.replica_id