Why do I have to SET ARITHABORT ON when using xml in sql server 2005?

Question

Why do I have to SET ARITHABORT ON when using xml in sql server 2005? I tried researching why I have to set this but couldn't find an answer that told me why. Only that it needs to be set.

Here is the specific error message I get when I take out the SET ARITHABORT ON line:

PARAMETER ERROR: INSERT LIST COULD NOT BE PARSED - INSERT failed because the following SET options have incorrect settings: 'ARITHABORT'. Verify that SET options are correct for use with indexed views and/or indexes on computed columns and/or query notifications and/or xml data type methods.

My stored procedure worked fine called from asp.net using odbc in one environment. Then when I moved it to another, I had to add SET ARITHABORT ON in the beginning of the stored procedure. I include the relevant sections of the stored procedure below. And the code that is calling it.

CREATE PROCEDURE [dbo].[myproc]
   @ruserid             varchar(8),
   @folder_list         xml,
   @insert_list         xml
AS

SET NOCOUNT ON
SET ARITHABORT ON

DECLARE @rindex integer
DECLARE @errormsg nvarchar(4000)
DECLARE @folder_cnt integer
DECLARE @insert_cnt integer


SET @rindex = -1

-- temp table to hold inserts
CREATE TABLE #insert_list (rowidx integer IDENTITY(1,1), insertdesc varchar(96) COLLATE database_default, insertfolder integer)

-- temp table to hold folders
CREATE TABLE #folder_list (rowidx integer IDENTITY(1,1), folderdesc varchar(144) COLLATE database_default, insertfolder integer)

-- insert inserts to make sure data is compatible in type
BEGIN TRY
   INSERT INTO #insert_list (insertdesc, insertfolder)
   SELECT insert_list.listitem.value('@insertdesc', 'varchar(96)'), insert_list.listitem.value('@insertfolder', 'integer')
   FROM @insert_list.nodes('/Root/Insert') AS insert_list(listitem)
END TRY
BEGIN CATCH
   SET @errormsg = N'PARAMETER ERROR: INSERT LIST COULD NOT BE PARSED - ' + ERROR_MESSAGE()
   RAISERROR(@errormsg, 16, 1)
   RETURN
END CATCH

-- insert folders to make sure data is compatible in type
BEGIN TRY
   INSERT INTO #folder_list (insertfolder, folderdesc)
   SELECT folder_list.listitem.value('@insertfolder', 'integer'), folder_list.listitem.value('@folderdesc', 'varchar(144)')
   FROM @folder_list.nodes('/Root/Folder') AS folder_list(listitem)
END TRY
BEGIN CATCH
   SET @errormsg = N'PARAMETER ERROR: FOLDER LIST COULD NOT BE PARSED - ' + ERROR_MESSAGE()
   RAISERROR(@errormsg, 16, 1)
   RETURN
END CATCH

-- insert rows
BEGIN TRANSACTION

BEGIN TRY

INSERT INTO my_folder_request (ruserid)
VALUES ( @ruserid )

SET @rindex = SCOPE_IDENTITY()

INSERT INTO my_insert_request (rindex, insertdesc, insertfolder)
SELECT @rindex, #insert_list.insertdesc, #insert_list.insertfolder
FROM #insert_list
ORDER BY #insert_list.rowidx

INSERT INTO my_folder_desc (rindex, insertfolder, folderdesc)
SELECT @rindex, #folder_list.insertfolder, #folder_list.folderdesc
FROM #folder_list
ORDER BY #folder_list.rowidx

END TRY
BEGIN CATCH
   IF @@TRANCOUNT > 0
      ROLLBACK TRANSACTION
   SET @errormsg = N'DATA INSERTION FAILED WITH MESSAGE - ' + ERROR_MESSAGE()
   RAISERROR(@errormsg, 16, 1)
   RETURN
END CATCH

IF @@TRANCOUNT > 0
   COMMIT TRANSACTION

-- return result
SELECT @rindex AS rindex

DROP TABLE #insert_list
DROP TABLE #folder_list

GO

Calling Code

  ' build odbc command for inserting creation request
  intRequestIndex = 0
  cmdAddRequest = New System.Data.Odbc.OdbcCommand
  cmdAddRequest.CommandType = CommandType.StoredProcedure
  cmdAddRequest.CommandTimeout = 60
  cmdAddRequest.CommandText = "{CALL myproc ( ?, ?, ?)}"

  ' add parameters to odbc command
  cmdAddRequest.Parameters.Add("@ruserid", OdbcType.VarChar, 8).Value = SafeODBCParamString(m_strUID)
  cmdAddRequest.Parameters.Add("@folder_list", OdbcType.NText).Value = System.Text.Encoding.Unicode.GetString(strmFolderList.ToArray())
  cmdAddRequest.Parameters.Add("@insert_list", OdbcType.NText).Value = System.Text.Encoding.Unicode.GetString(strmInsertList.ToArray())

  ' run odbc command returning info about results
  cmdAddRequest.Connection = Me.ODBCConnection()
  Try
     rdrRequestData = cmdAddRequest.ExecuteReader(CommandBehavior.CloseConnection)

Answer 1

Unless you are creating XML indexes you should not need to set ARITHABORT to ON. That said I know that there are some performance problems when using ADO.NET (which I believe sets ARITHABORT to OFF) It does not hurt having it ON because it will terminate a query when an overflow or divide-by-zero error occurs during query execution.

Answer 2

I'm thinking this statement from books online kind of hints at it: "SET ARITHABORT must be ON when you are creating or changing indexes on computed columns or indexed views." So the nodes method must be creating an indexed view internally or something. But this is just an educated guess.