Alternatives to XML shredding in SQL

Question

I tried to shred XML into a temporary table by using XQuery .nodes as follows. But, I got performance problem. It is taking much time to shred. Please give me an idea on alternatives for this.

My requirement is to pass bulk records to a stored procedure and parse those records and do some operation based on record values.

 CREATE TABLE #DW_TEMP_TABLE_SAVE(  
[USER_ID] [NVARCHAR](30), 
[USER_NAME] [NVARCHAR](255)
)   

insert into #DW_TEMP_TABLE_SAVE
   select 
       A.B.value('(USER_ID)[1]', 'nvarchar(30)' ) [USER_ID], 
       A.B.value('(USER_NAME)[1]', 'nvarchar(30)' ) [USER_NAME]
   from 
       @l_n_XMLDoc.nodes('//ROW') as A(B) 

Answer 1

Specify the text() node in your values clause.

insert into #DW_TEMP_TABLE_SAVE
select A.B.value('(USER_ID/text())[1]', 'nvarchar(30)' ) [USER_ID], 
       A.B.value('(USER_NAME/text())[1]', 'nvarchar(30)' ) [USER_NAME]
from @l_n_XMLDoc.nodes('/USER_DETAILS/RECORDSET/ROW') as A(B)

Not using text() will create a query plan that tries concatenate the values from the specified node with all its child nodes and I guess you don't want that in this scenario. The concatenation part of the query if you don't use text() is done by the UDX operator and it is a good thing not to have it in your plan.

Another thing to try is OPENXML . In some scenarios (large xml documents) I have found that OPENXML performs faster.

declare @idoc int
exec sp_xml_preparedocument @idoc out, @l_n_XMLDoc

insert into #DW_TEMP_TABLE_SAVE
select USER_ID, USER_NAME
from openxml(@idoc, '/USER_DETAILS/RECORDSET/ROW', 2) 
  with (USER_ID  nvarchar(30), USER_NAME nvarchar(30))

exec sp_xml_removedocument @idoc