Question

We have a performance problem which narrows down to our app-server. One possible suspect is that in some cases, the time to compile the Linq2Entity query becomes unreasonably long.
We’re extending our logging system to include the executed sql.
I plan to use the .ToString() method of IQueriable to obtain the sql.

1. Will this force EF to compile the query?
2. Will EF use this plan when we enumerate the IQueriable and avoid recompiling the query?
3. Is there any downside to this?

Answer 1

1. Yes – EF will run your query through the query pipeline (including the provider which generates the actual SQL query),
2. It depends – if you use EF on .NET Framework 4.5 queries are automatically compiled and cached (see performance considerations for more details).
3. Probably not if queries are compiled and cached.