There are, unfortunately, some times when developers refuse to put the ORM down.
I mean, it’s mostly unfortunate for them, because they’ll continue to have performance problems.
Me? I’ll be okay.
The items in this post are issues I’ve run into constantly when working with people who use ORMs, but don’t spend any time looking at the queries they generate.
I expect this list to grow. Heck, maybe it’ll even get some good comments that I can add to the list.
I know, I know. Good comments.
Here’s the stuff I see quite frequently causing issues with ORM code, in no particular order, and they’re quite often signs that you’d be better off with a stored procedure.
1. Your select list doesn’t fit in the cached plan
2. Your queries generates long IN lists
3. You don’t understand the query it generates
Because you-know-who, did you-know-what, with you-know-who, but let’s keep that between me and you isn’t a good way to send queries to SQL Server. The number of far overly-complicated queries that generate unrecognizable logic that I’ve seen have, at this point, probably generated physical weight in the world beyond mere electrons. The 20 lines of code you wrote to explain what you want have turned into a 200 line query full of derived left joins to every single imaginable relation in the database. Why? I don’t know. You don’t know either.
4. You can’t get a good query plan
5. You can’t get developers to fully parameterize queries
There are many ways to tune a query, but unfortunately a good portion of them are unavailable while using ORMs in their natural code-only state. Sure, you can write custom queries in the code, but that has a lot of potential downsides, too. Depending on how the code is constructed, and if parameters are strongly typed, you may not get consistent plan re-use.
I’m all for application developers using tooling that enables them to work on new features quickly and in a way that they’re comfortable with. But at some point, SQL developers or DBAs need to step in and enforce coding standards. At some point, mom and dad have to the keys away and implement something that performs beyond just what “works”.
Thanks for reading!