WAITFOR Wait Type in SQL Server

Part of the SQL Server Wait Types Library.
Related deep dive: SOS_SCHEDULER_YIELD Wait Type.

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WAITFOR is the most literal wait type in the DMV: it records sessions executing a WAITFOR DELAY or WAITFOR TIME statement. The duration is exactly what the T-SQL asked for. Nothing is contended and nothing is slow; somebody’s code chose to sleep.

That makes it user-initiated by definition, and normally filtered out of analysis.

Is It a Problem?

Not as a performance signal. As a code-inventory signal, occasionally: if WAITFOR carries the most accumulated wait time on an instance, something is sleeping a great deal, and it is worth knowing what. The classics are polling loops (WHILE ... WAITFOR DELAY '00:00:05') in queue-processing procedures, retry loops with sleeps, and the occasional debug WAITFOR accidentally left in deployed code.

One genuine caution: a session sleeping inside an open transaction holds its locks while it sleeps, and that can block others. The victim’s wait would show as LCK_M_*, with the sleeper as head blocker.

Common Causes

• Deliberate polling or throttling loops in application and job code.
• Debug delays left behind in deployed procedures.
• Scheduled coordination hacks (WAITFOR TIME) inside long-running jobs.

What To Do

1. Find the sleepers when curious: sys.dm_exec_requests WHERE wait_type = 'WAITFOR' with the SQL text tells you who and why.
2. Replace hot polling loops with better patterns where it matters (Service Broker activation, shorter poll intervals only when work exists).
3. Make sure nothing sleeps inside an open transaction; that is the one way WAITFOR hurts others.

How To See It

Rank waits with Get-WaitStatistics; it is filtered as user-initiated. Check the live DMV when you want to know who is napping.

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