Category: Wait Types

WAIT_XTP_OFFLINE_CKPT_LOG_IO is recorded when an In-Memory OLTP offline checkpoint thread waits for a log read I/O to complete. The XTP checkpoint mechanism continuously scans the transaction log for changes to memory-optimized tables and folds them into checkpoint file pairs; when the scanner has to physically read log from disk, the read time lands here. Its…

WAIT_XTP_RECOVERY is recorded when database recovery waits for the recovery of memory-optimized objects to finish. It appears during crash recovery, after failovers and restores, and around certain database state changes (offline to online, read-only to read-write). Memory-optimized tables must be fully reloaded into memory from checkpoint files and log before the database is usable. The…

WAIT_XTP_TASK_SHUTDOWN is recorded while a thread waits for an In-Memory OLTP thread to complete and shut down. XTP runs its own background threads (checkpoint workers, garbage collection helpers), and orderly teardown, at database offline, instance shutdown, or internal reorganisation, means waiting for them to finish. Lifecycle machinery, active at endings. Is It a Problem? No;…

WAITFOR_PER_QUEUE is recorded when a Service Broker worker thread waits for a message on a specific queue as part of an activation procedure’s WAITFOR (RECEIVE …). Each wait runs up to the statement’s timeout, or 60 seconds when none is specified, then the loop typically re-issues the receive. It is the queue-scoped cousin of BROKER_RECEIVE_WAITFOR,…

WRITE_COMPLETION appears when a thread waits for a synchronous file write to finish. Ordinary dirty-page flushing goes through checkpoint and the lazy writer (showing up as other waits), so WRITE_COMPLETION covers the special cases: writes to database snapshot files, certain metadata writes, and other file operations the engine performs synchronously. The database snapshot angle is…

XE_BUFFERMGR_ALLPROCESSED_EVENT is recorded on a background thread while Extended Events session buffers are flushed to their targets, waiting for the “all buffers processed” signal. Flush-everything moments happen at session stops, target-state queries, and checkpoint-like operations inside the XE engine. Part of the XE delivery machinery, alongside the dispatcher and timer waits. Is It a Problem?…

XE_DISPATCHER_WAIT is recorded by the background dispatcher threads that serve Extended Events asynchronous targets, while they wait for filled event buffers to process. Events accumulate in session buffers; when a buffer is ready (full, or past its dispatch latency), a dispatcher picks it up and delivers it to the target. Between deliveries, the dispatchers sit…

XE_FILE_TARGET_TVF is recorded while a thread performs operations for a query reading event data from an Extended Events file target via sys.fn_xe_file_target_read_file, the function behind most XE analysis queries, including reading system_health files. It is a preemptive wait, so the thread stays on the processor until the read operation completes. Every time you (or a…

XE_LIVE_TARGET_TVF is recorded while a thread services a query that pulls data from an Extended Events live data stream, most commonly the “Watch Live Data” viewer in SSMS. The live target streams events to the watching client as they occur, and the serving thread accumulates this wait while that stream is open. It is a…