If your tables gets so many query, your query results take so long time. Avoid this issue, you can use SQL NOLOCK in your sql queries or following linq to sql code heps to do this.

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using (var t = new TransactionScope(TransactionScopeOption.Required,

    new TransactionOptions { IsolationLevel = System.Transactions.IsolationLevel.ReadUncommitted } ))

{

   // Your linq query goes here.

}

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I'm looking for that how can I use this as default in my queries.

When I found it, let you know.

Also you can find more information above about isolation level subject

http://www.hanselman.com/blog/GettingLINQToSQLAndLINQToEntitiesToUseNOLOCK.aspx

hope this helps