Performance Tuning with SQL Server Dynamic Management Views

Chapter 3: Query Plan Metadata
Investigating Expensive Cached
Stored Procedures
New to SQL Server 2008 is the sys.dm_exec_procedure_stats DMV that focuses
only on stored procedures and will not require you to aggregate on sql_handle to get
an overall view of your object's performance characteristics. Books Online describes it as:
Returns aggregate performance statistics for cached stored procedures. The view contains one row per stored
procedure, and the lifetime of the row is as long as the stored procedure remains cached. When a stored
procedure is removed from the cache, the corresponding row is eliminated from this view. At that time, a
Performance Statistics SQL trace event is raised similar to sys.dm_exec_query_stats.
It is similar in nature to sys.dm_exec_query_stats, but with a few differences in the
columns available. It only links to the plan of the procedure or object, not the individual
statements in the procedure. This DMV allows you to discover a lot of very interesting
and important performance information about your cached stored procedures.
-- Top Cached SPs By Total Logical Reads (SQL 2008 only).
-- Logical reads relate to memory pressure
SELECT TOP ( 25 )
p.name AS [SP Name] ,
deps.total_logical_reads AS [TotalLogicalReads] ,
deps.total_logical_reads / deps.execution_count AS [AvgLogicalReads] ,
deps.execution_count ,
ISNULL(deps.execution_count / DATEDIFF(Second, deps.cached_time,
GETDATE()), 0) AS [Calls/Second] ,
deps.total_elapsed_time ,
deps.total_elapsed_time / deps.execution_count AS [avg_elapsed_time] ,
deps.cached_time
FROM sys.procedures AS p
INNER JOIN sys.dm_exec_procedure_stats
AS deps ON p.[object_id] = deps.[object_id]
WHERE deps.database_id = DB_ID()
ORDER BY deps.total_logical_reads DESC ;
Listing 3.16: Investigating logical reads performed by cached stored procedures.
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