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Always On Synch Lag
by BF (Principal Consultant; Architecture; Engineering)
2022-05-20








Always On Synch Lag


;WITH
AG_Stats AS
(
SELECT AR.replica_server_name,
HARS.role_desc,
Db_name(DRS.database_id) [DBName],
DRS.last_commit_time
FROM sys.dm_hadr_database_replica_states DRS
INNER JOIN sys.availability_replicas AR ON DRS.replica_id = AR.replica_id
INNER JOIN sys.dm_hadr_availability_replica_states HARS ON AR.group_id = HARS.group_id
AND AR.replica_id = HARS.replica_id
),
Pri_CommitTime AS
(
SELECT replica_server_name
, DBName
, last_commit_time
FROM AG_Stats
WHERE role_desc = 'PRIMARY'
),
Sec_CommitTime AS
(
SELECT replica_server_name
, DBName
, last_commit_time
FROM AG_Stats
WHERE role_desc = 'SECONDARY'
)
SELECT
p.replica_server_name [Primary Replica]
, p.[DBName] AS [Database Name]
, s.replica_server_name [Secondary Replica]
, p.last_commit_time [Primary Last Commit]
, s.last_commit_time [Secondary Last Commit]
, DATEDIFF(MS,s.last_commit_time,p.last_commit_time) AS [Sync Lag Milliseconds]
FROM Pri_CommitTime p
LEFT JOIN Sec_CommitTime s ON [s].[DBName] = [p].[DBName]