MAXDOP well where to start.

The first encounter of this was with SQL 7. a very badly written statment resulted in an almost infite loop due to the parallel processes not getting back together.

My view is that if you have a well defined statement then the default works well. However if you are resulting in large rowsets in your query i.e two sub queries returning lots or rows that then have to be joined, then using MAXDOP is a serious consideration.

When handling large sets of data within a query I have often seen SQL choose a parallel query plan that results in the query not completing.

Simon Sabin

Co-author of SQL Server 2000 XML Distilled

http://www.amazon.co.uk/exec/obidos/ASIN/1904347088