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Im looking for otimization.
When I call Count method in Entity Framework, does it process all the columns or only one or what?
If you also have any official site talking about this, I would appreciate.
Thank you.
I did some tests a while ago and found out that EF does a count on the server, it sends a query with a SELECT COUNT so it does not load all records for sure.
about the columns, if you are referring to the difference between
COUNT(*)orCOUNT(Id)orCOUNT(1)I have read somewhere a while ago that for SQL Server there is no difference, theCOUNT(*)is optimized asCOUNT(1)anyway.you could read many articles online or question here on SO… not excatly 100% what you asked but similar topics on performances of EF and ORM…
How to COUNT rows within EntityFramework without loading contents?
http://ayende.com/blog/4387/what-happens-behind-the-scenes-nhibernate-linq-to-sql-entity-framework-scenario-analysis
How to optimize Entity Framework Queries