CHECKPOINT_QUEUE wait type is a background wait type related to the checkpoint process in SQL Server that is responsible for writing modified (dirty) data pages from the buffer cache to the data file on disk. In most cases, this wait type can be ignored and this is something that most DBAs should be aware of. The CHECKPOINT_QUEUE indicates that the checkpoint process is waiting for work. If you notice this wait type, there shouldn’t be any potential performance issues in most cases. Additionally, it specifies the checkpoint processes spent waiting on work.
If you notice
high values of CHECKPOINT_QUEUE wait type, then probably your SQL Server instance
is not busy. It means that the SQL Server is expecting some work to come
in.
The CHECKPOINT_QUEUE
wait type gets recorded in the sys.dm_os_wait_stats and sys.dm_os_waiting_tasks
DMVs.
Here is a
sample recording of values in both DMVs.
sys.dm_os_wait_stats:
sys.dm_os_waiting_tasks:
Something interesting to note is that both the DMVs are interlinked. Firstly, the value gets records in sys.dm_os_waiting_tasks once the automatic checkpoint occurs. Secondly, the SQL Server internally executes to move the record from sys.dm_os_waiting_tasks to sys.dm_os_wait_stats and reset the value in sys.dm_os_waiting_tasks to 0.
If you ever experience a high value of CHECKPOINT_QUEUE in sys.dm_os_waiting_tasks then the automatic checkpoint happened sometime back in your SQL Server instance.
Bottomline
The CHECKPOINT_QUEUE wait type is related to checkpoint operations inside SQL Server. They are not any indications of performance issues. The wait type is normal for SQL Server instances and can be safely ignored. The wait type value will be high because the SQL Server instance is waiting for more work to come in. The value gets recorded in the sys.dm_os_wait_stats and sys.dm_os_waiting_tasks.
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