The wait type HADR_TRANSPORT_FLOW_CONTROL is ranked #262 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.
SQL Server Always On Availability Groups rely on efficient data transport to keep replicas synchronized. During this process, you might encounter the HADR_TRANSPORT_FLOW_CONTROL wait type. Understanding this wait can help you troubleshoot synchronization issues and ensure your Always On setup operates smoothly. What is HADR_TRANSPORT_FLOW_CONTROL?The HADR_TRANSPORT_FLOW_CONTROL wait type occurs when SQL Server is managing the flow of data between the primary replica and secondary replicas. It specifically relates to situations where SQL Server temporarily pauses data transmission to avoid overloading the receiving replica or network. This wait type helps maintain balance and prevent excessive resource usage. In simpler terms, this wait type indicates that SQL Server is pacing the flow of data to ensure stability and avoid congestion. While some waits are expected during normal operations, excessive or prolonged waits could signal underlying performance or configuration issues. Why Does HADR_TRANSPORT_FLOW_CONTROL Happen?Several factors can lead to HADR_TRANSPORT_FLOW_CONTROL waits, including:
Addressing these factors can help reduce these waits and improve synchronization performance. How to Monitor HADR_TRANSPORT_FLOW_CONTROL WaitsMonitoring HADR_TRANSPORT_FLOW_CONTROL waits is essential for identifying patterns and pinpointing issues in Always On Availability Groups. The Database Health Monitor provides an excellent way to track this wait type. Its Historic Waits Monitoring feature allows you to observe when these waits occur, their frequency, and their correlation with system events. With Database Health Monitor, you can identify whether these waits stem from network issues, resource limitations, or workload imbalances and take corrective action to optimize your environment. What Can You Do About HADR_TRANSPORT_FLOW_CONTROL Waits?If you notice frequent or prolonged HADR_TRANSPORT_FLOW_CONTROL waits, consider taking these actions:
These steps can help you reduce transport flow control waits and improve the overall performance of your Always On setup. Why Use Database Health Monitor?The Database Health Monitor is a comprehensive tool for tracking SQL Server wait types, including HADR_TRANSPORT_FLOW_CONTROL. Its Historic Waits Monitoring feature provides actionable insights into wait trends, helping you identify and address performance bottlenecks in your Always On Availability Groups. With Database Health Monitor, you can keep your SQL Server environment running efficiently and reliably. Start using Database Health Monitor today to monitor and optimize your SQL Server’s performance, ensuring a resilient and high-performing database system!
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_SYNC_COMMIT HADR_SYNCHRONIZING_THROTTLE HADR_TDS_LISTENER_SYNC HADR_TDS_LISTENER_SYNC_PROCESSING HADR_TIMER_TASK HADR_TRANSPORT_DBRLIST HADR_TRANSPORT_SESSION HADR_WORK_POOL HADR_WORK_QUEUE HADR_XRF_STACK_ACCESS See AlsoAll Wait Types |