Query the plan cache for scan and seek operations for a particular index

Question

Can you please help me in querying the plan cache in order to see which queries perform a scan and which queries perform a seek operation for a particular (nonclustered) index? I'm on SQL Server 2008 R2?

Answer 1

You will need to dig into query plans to identify if a particular query is performing a scan instead a seek, but you can (relatively) quickly identify what queries are using a particular index by running the following:

USE DatabaseName
GO

SELECT DISTINCT TOP 100 
        s.total_logical_reads / s.execution_count
    , SUBSTRING(t.TEXT, (s.statement_start_offset / 2) + 1, (
            (
                CASE s.statement_end_offset
                    WHEN - 1
                        THEN DATALENGTH(t.TEXT)
                    ELSE s.statement_end_offset
                    END - s.statement_start_offset
                ) / 2
            ) + 1) AS statement_text
    , s.execution_count AS ExecutionCount
    , s.max_elapsed_time AS MaxElapsedTime
    , ISNULL(s.total_elapsed_time / s.execution_count, 0) AS AvgElapsedTime
    , s.creation_time AS LogCreatedOn
    , *
FROM sys.dm_exec_query_stats s
CROSS APPLY sys.dm_exec_sql_text(s.sql_handle) t
WHERE TEXT LIKE '%Table_or_View_Index_Is_Defined_On%'
    AND TEXT NOT LIKE '%sys.dm_exec_query_stats s%'
ORDER BY s.total_logical_reads / s.execution_count DESC

Depending on what your end-goal is, you can adjust the ordering on this to your liking.

Once you identify a query that you want to dig into further, then pull up it's execution plan via:

SELECT query_plan 
FROM sys.dm_exec_query_plan(PLAN_HANDLE_FROM_ABOVE_RESULTSET)