SQL SERVER: Find plan cache queries using user defined functions

FindQueriesUsingUDFs.sql

-- Finds cached plans whose showplan XML contains a UDF reference,
-- and tags them by DML statement type (SELECT/INSERT/UPDATE/DELETE/MERGE).

WITH XMLNAMESPACES ('http://schemas.microsoft.com/sqlserver/2004/07/showplan' AS p)
SELECT
    udf_ref.value('@Database', 'sysname') AS udf_database,
    udf_ref.value('@Schema',   'sysname') AS udf_schema,
    udf_ref.value('@Table',    'sysname') AS udf_name,   -- showplan (oddly) labels UDF names with @Table
    CASE
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'INSERT%' THEN 'INSERT'
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'UPDATE%' THEN 'UPDATE'
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'DELETE%' THEN 'DELETE'
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'MERGE%'  THEN 'MERGE'
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'SELECT%' THEN 'SELECT'
        WHEN UPPER(LTRIM(stmt_text)) LIKE 'WITH%'   THEN 'SELECT (CTE)'
        ELSE 'OTHER'
    END AS statement_type,
    cp.objtype,
    DB_NAME(st.dbid)                          AS outer_database,
    OBJECT_SCHEMA_NAME(st.objectid, st.dbid)  AS outer_object_schema,
    OBJECT_NAME(st.objectid, st.dbid)         AS outer_object_name,
    cp.usecounts,
    qs.execution_count,
    qs.total_worker_time,
    qs.total_elapsed_time,
    qs.total_logical_reads,
    stmt_text                                 AS statement_text,
    st.text                                   AS full_batch_text,
    qp.query_plan
FROM sys.dm_exec_cached_plans cp
CROSS APPLY sys.dm_exec_query_plan(cp.plan_handle) qp
CROSS APPLY sys.dm_exec_sql_text(cp.plan_handle)   st
CROSS APPLY qp.query_plan.nodes('//p:UDF') AS u(udf_ref)
OUTER APPLY (
    SELECT TOP 1 qs.*
    FROM sys.dm_exec_query_stats qs
    WHERE qs.plan_handle = cp.plan_handle
    ORDER BY qs.execution_count DESC
) qs
OUTER APPLY (
    SELECT SUBSTRING(
        st.text,
        (ISNULL(qs.statement_start_offset, 0) / 2) + 1,
        (( CASE ISNULL(qs.statement_end_offset, -1)
             WHEN -1 THEN DATALENGTH(st.text)
             ELSE qs.statement_end_offset
           END - ISNULL(qs.statement_start_offset, 0)) / 2) + 1
    ) AS stmt_text
) s
WHERE qp.query_plan IS NOT NULL
  AND cp.objtype IN ('Adhoc', 'Prepared', 'Proc', 'Trigger')   -- tighten as needed
ORDER BY qs.execution_count DESC, cp.usecounts DESC;