September 22, 2010 at 7:29 am
I have a query that run in 3 seconds when executed with hint OPTION (MAXDOP 1), but the same query run in 20 seconds when run without this hint and with degree parallelism configured to 1 in Workloud Group of this user in Resource Governor. The maxdop of resource governor don't work the same way of hint?
SQL 2008 R2 Enterprise
Windows 2008 R2 Standard x64
September 22, 2010 at 2:59 pm
http://support.microsoft.com/kb/329204
In SQL Server 2008, if MAXDOP exceeds the value that was configured by using the Resource Governor, the Database Engine uses the Resource Governor MAXDOP value. All semantic rules that are used with the max degree of parallelism configuration option are applicable when you use the MAXDOP query hint.
September 22, 2010 at 3:01 pm
http://support.microsoft.com/kb/970399
This problem occurs because the query optimizer ignores the option when it is set to a value larger than 1. Therefore, the estimated degree of parallelism computation does not include the option.
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The fix for this issue was first released in Cumulative Update 3 for SQL Server 2008 Service Pack 1.
May 29, 2014 at 11:18 am
This is happening to me as well. I am using SQL Server 2012 and have resource governer configured for MAX DOP as 1 but it does not work because the query still runs in 1 min and with MAXDOP 1 option it runs in 10 seconds. Any help please?
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