Record the understanding of this join and refine it.
1. Usage of statistics:
Empty the command used to execute the plan
DBCC FREEPROCCACHE
Empty the cache command inside the buffer pool
DBCC DROPCLEANBUFFERS
The two commands above can be performed before the SET STATISTICS command is executed
1. Set STATISTICS TIME on
Example
Set STATISTICS TIME on
Go
Select COUNT (1) from zwkmye2017
Go
Set STATISTICS time off
Go
Returns the time that the statement was executed:
Main analysis and compile time
CPU time corresponds to the amount of time the CPU spends purely
Elapsed time is the amount of time it takes to take this step.
and the execution time.
is the same.
2. Set STATISTICS IO on
As the name implies, mainly displays IO-related information
3. Set STATISTICS PROFILE on
Displays the execution plan and the information that is actually returned by the execution of the statement.
[Reading notes] SQL Server Enterprise Platform Management practice reading notes 02