Detect Convert_Implicit usages I suspect that my Sql Server is using CONVERT_IMPLICIT a lot because many of my fields are set as string in NHibernate while they are set as varchar in database.
Is there any option to detect when server is using The CONVERT_IMPLICIT function?

Thanks
Stolen unceremoniously from Jonathan Kehayias, this will find all the plans relevant to the current database that contain implicit converts (be aware that this is not fast):

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED 

DECLARE @dbname SYSNAME 
SET @dbname = QUOTENAME(DB_NAME()); 

WITH XMLNAMESPACES 
   (DEFAULT 'http://schemas.microsoft.com/sqlserver/2004/07/showplan') 
SELECT 
   stmt.value('(@StatementText)[1]', 'varchar(max)'), 
   t.value('(ScalarOperator/Identifier/ColumnReference/@Schema)[1]', 'varchar(128)'), 
   t.value('(ScalarOperator/Identifier/ColumnReference/@Table)[1]', 'varchar(128)'), 
   t.value('(ScalarOperator/Identifier/ColumnReference/@Column)[1]', 'varchar(128)'), 
   ic.DATA_TYPE AS ConvertFrom, 
   ic.CHARACTER_MAXIMUM_LENGTH AS ConvertFromLength, 
   t.value('(@DataType)[1]', 'varchar(128)') AS ConvertTo, 
   t.value('(@Length)[1]', 'int') AS ConvertToLength, 
   query_plan 
FROM sys.dm_exec_cached_plans AS cp 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp 
CROSS APPLY query_plan.nodes('/ShowPlanXML/BatchSequence/Batch/Statements/StmtSimple')    
  AS batch(stmt) 
CROSS APPLY stmt.nodes('.//Convert[@Implicit="1"]') AS n(t) 
JOIN INFORMATION_SCHEMA.COLUMNS AS ic 
   ON QUOTENAME(ic.TABLE_SCHEMA)
    = t.value('(ScalarOperator/Identifier/ColumnReference/@Schema)[1]', 'varchar(128)') 
   AND QUOTENAME(ic.TABLE_NAME)
    = t.value('(ScalarOperator/Identifier/ColumnReference/@Table)[1]', 'varchar(128)') 
   AND ic.COLUMN_NAME
    = t.value('(ScalarOperator/Identifier/ColumnReference/@Column)[1]', 'varchar(128)') 
WHERE 
t.exist('ScalarOperator/Identifier/ColumnReference[@Database=sql:variable("@dbname")][@Schema!="[sys]"]')
 = 1


You might also find these useful:

http://www.sqlperformance.com/2013/04/t-sql-queries/implicit-conversion-costs

http://www.sqlskills.com/blogs/jonathan/implicit-conversions-that-cause-index-scans/