| The wait type HADR_SYNC_COMMIT is ranked #47 by Stedman Solutions and Database Health Monitor. Wait statistics, in the context of SQL Server, refer to the amount of time that a query spends waiting to access data in the database. When a client application requests data from the database, the request is placed in a queue and the client application must wait for its turn to access the data. The time that the query spends waiting is called a "wait" and is tracked by SQL Server. This information can be used to identify potential performance bottlenecks and optimize the performance of the database. Wait statistics are commonly used by database administrators to diagnose and troubleshoot performance issues in SQL Server. In order to ensure the availability and durability of data, SQL Server uses a technology called "Always On Availability Groups" (AAG) to replicate data across multiple servers and automatically fail over in the event of a server failure. One of the wait types associated with AAG is called HADR_SYNC_COMMIT. This wait type is triggered when a SQL Server process is committing a transaction to the local database and is waiting for the transaction to be replicated to the secondary replicas in the AAG. When a SQL Server process performs a write operation, such as inserting, updating, or deleting data, it must first commit the changes to the local database. This involves writing the changes to the database files and updating the transaction log. Once the changes have been committed to the local database, they must then be replicated to the secondary replicas in the AAG. This is done to ensure that the data remains available and consistent across all replicas in the AAG. The process of replicating the changes to the secondary replicas can sometimes take some time, depending on the size and complexity of the transaction. In these cases, the SQL Server process will wait for the replication to complete before it can continue with its work. This waiting is what is known as a HADR_SYNC_COMMIT wait. While the HADR_SYNC_COMMIT wait type is generally not a cause for concern, it can sometimes indicate a performance issue if it is occurring frequently or for long periods of time. In these cases, it may be necessary to investigate the cause of the issue and take steps to improve performance, such as optimizing the replication process or increasing the systems resources. Overall, the HADR_SYNC_COMMIT wait type is an important part of how SQL Server uses AAG to ensure the availability and durability of data. By understanding this wait type and its potential impact on performance, database administrators can ensure that their systems are running efficiently and effectively.
Applies toRelated WaitsHADR_AG_MUTEXHADR_AR_CRITICAL_SECTION_ENTRY HADR_AR_MANAGER_MUTEX HADR_AR_UNLOAD_COMPLETED HADR_ARCONTROLLER_NOTIFICATIONS_SUBSCRIBER_LIST HADR_BACKUP_BULK_LOCK HADR_BACKUP_QUEUE HADR_CLUSAPI_CALL HADR_COMPRESSED_CACHE_SYNC HADR_CONNECTIVITY_INFO HADR_DATABASE_FLOW_CONTROL HADR_DATABASE_VERSIONING_STATE HADR_DATABASE_WAIT_FOR_RESTART HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING HADR_DB_COMMAND HADR_DB_OP_COMPLETION_SYNC HADR_DB_OP_START_SYNC HADR_DBR_SUBSCRIBER HADR_DBR_SUBSCRIBER_FILTER_LIST HADR_DBSEEDING HADR_DBSEEDING_LIST HADR_DBSTATECHANGE_SYNC HADR_FABRIC_CALLBACK HADR_FILESTREAM_BLOCK_FLUSH HADR_FILESTREAM_FILE_CLOSE HADR_FILESTREAM_FILE_REQUEST HADR_FILESTREAM_IOMGR HADR_FILESTREAM_MANAGER HADR_GROUP_COMMIT HADR_LOGCAPTURE_SYNC HADR_LOGCAPTURE_WAIT HADR_LOGPROGRESS_SYNC HADR_NOTIFICATION_DEQUEUE HADR_NOTIFICATION_WORKER_EXCLUSIVE_ACCESS HADR_NOTIFICATION_WORKER_STARTUP_SYNC HADR_NOTIFICATION_WORKER_TERMINATION_SYNC HADR_PARTNER_SYNC HADR_READ_ALL_NETWORKS HADR_RECOVERY_WAIT_FOR_CONNECTION HADR_RECOVERY_WAIT_FOR_UNDO HADR_REPLICAINFO_SYNC HADR_SYNCHRONIZING_THROTTLE HADR_TDS_LISTENER_SYNC HADR_TDS_LISTENER_SYNC_PROCESSING HADR_TIMER_TASK HADR_TRANSPORT_DBRLIST HADR_TRANSPORT_FLOW_CONTROL HADR_TRANSPORT_SESSION HADR_WORK_POOL HADR_WORK_QUEUE HADR_XRF_STACK_ACCESS See AlsoAll Wait Types |  |
