How
do I know Stored Procedure is slowly running or doesn't have any performance
issue?
After creating Stored Procedure, you must have a
look at the Query Execution Plan. If
you have Index/Table scan and also if it says that there are missing index then
there is a performance issue and it is possible to fine-tune it.
Optimization
Tips To Increase SQL Server Stored Procedure Performance -
1. Use
stored procedures instead of heavy-duty queries.
2. Include
the SET NOCOUNT ON statement into your stored procedures to stop the message
indicating the number of rows affected by a Transact-SQL statement.
3. Call
stored procedure using its fully qualified name.
4. Consider
returning the integer value as a RETURN statement instead of an integer value
as part of a recordset.
5. Don't
use the prefix "sp_" in the stored procedure name if you need to
create a stored procedure to run in a database other than the master database.
6. Use
EXISTS() instead of COUNT().
7. Don’t
use functions in the WHERE clause.
8. Use
Join query instead of sub-query and co-related subquery.
9. Use
the sp_executesql stored procedure instead of the EXECUTE statement.
10. Use
sp_executesql stored procedure instead of temporary stored procedures.
11. If
you have a very large stored procedure, try to break down this stored procedure
into several sub-procedures, and call them from a controlling stored procedure.
12. Try
to avoid using temporary tables inside your stored procedure.
13. Try
to avoid using DDL (Data Definition Language) statements inside your stored
procedure.
14. Add
the WITH RECOMPILE option to the CREATE PROCEDURE statement if you know that
your query will vary each time it is run from the stored procedure.
15. Use
Index for required columns - Index should be created for all columns which are
using Where, Group By, Order By, Top, and Distinct command.
16. Try
to Avoid Correlated Queries i.e. Select Name, City, (Select Company_Name from
Company where companyId=cs.CustomerId) from Customer cs
17. Try
to Avoid Loops In Coding i.e. declare @int int;
set @int=1; while
@int<=100 begin Insert Into Tab
values(@int,'Value'+@int); set
@int=@int+1; end
18. Importance
of Column Order in the index -If we are creating a Non-Clustered index on more
than one column then we should consider the sequence of the columns. The order
or position of a column in an index also plays a vital role in improving SQL
query performance. An index can help to improve the SQL query performance if
the criteria of the query match the columns that are left most in the index
key. So we should place the most selective column at the leftmost side of a
non-clustered index.
19. Try
to Drop Index before Bulk Insertion of Data.
20. Use
Sparse Column - Sparse column provide better performance for NULL and Zero
data. If you have any columns that contain large amount numbers of NULL and
Zero then prefer Sparse Column instead of default column of SQL Server. The
sparse column takes lesser space than the regular column (without SPARSE
clause).
21. Don't
use the Index if the size of the table is very small.
22. Use
View for complex queries.
23. Use
Full-text Index if your query contains multiple wild card searches using
LIKE(%%), then the use of the Full-text Index can increase the performance.
24. Try
to avoid * and specify column names instead of using * in a SELECT statement.