It can be used to test the performance of SQL statements or stored procedures.
Checkpoint -- Used to check the changed data pages or log pages in the current working database, and forcibly write the data from the data buffer to the hard disk.
Go
DBCC Freeproccache -- Delete all buffers from the buffer pool
DBCC Dropcleanbuffers -- Delete all elements from the process Cache
Go
DBCC Freesystemcache ( ' All ' ); -- Clear the scheduler cache of an SQL instance
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Set Statistics Io On
Set Statistics Time On
Go
-- -------------------------
Declare @ B Datetime
Declare @ E Datetime
Set @ B = Getdate ();
Select Count ( * ) From Test1;
Set @ E = Getdate ();
Select Datediff (MS, @ B , @ E )
-- --------------------------
Set Statistics Io Off
Set Statistics Time Off
Go
DBCC Dropcleanbuffers
DBCC Freeproccache
The execution result is as follows :---------------------------------------------------------
