Entity Framework Developers Clamor for Better SQL Generation

"I have seen simple select statements [in Entity Framework] with 4 or 5 includes result in nearly 5,000 line SQL statements when an equivalent hand-written SQL statement is [about] 15 lines."

So reads the first of 21 comments on Microsoft's "ADO.NET Entity Framework (EF) Feature Suggestions" site, where developers can post, vote and comment on proposed EF enhancements. "Improved SQL Generation" is by far the No. 1 feature suggestion, with some 1,400 votes.

Several developer complaints about SQL generation concerned bloated code or slow performance. You saw an example of the former; the latter is exemplified by this comment:

"I just documented a case where the Contains() operator reduces EF query performance by a factor of 300. Further diagnosis revealed that the slowdown occurs in the query-generation portion of the request, so I agree that this needs some serious attention."

Microsoft's Diego Vega, program manager for DataFx, responded that the core EF library update coming in .NET 4.5 will provide better SQL generation in some cases, but not for all of the listed scenarios. "I am going to leave this idea as open for now, until we figure out a better way to track individual scenarios, which we need to do to get more actionable data," Vega said.

Speaking of .NET 4.5 and EF core libraries, some comments concerned the attempted separation of EF releases from .NET. The EF team shipped the first two releases as part of the .NET Framework, but then released separate updates to get them out to developers faster, as mentioned in this October blog post. That post said the June 2011 CTP was the first attempted full EF shipment separate from the .NET Framework. But technical problems resulted, so several feature improvements -- such as support for enums, spatial types and others -- that rely on .NET core library updates will have to wait for next EF preview that will ship along with the upcoming public preview of .NET 4.5.

When Vega reiterated this on the feature request page, a couple of readers found fault with that, as evidenced by this comment:

"Diego, No offense but moving to v4.5 of the framework is really not an option for ... most corporate software."

And this:

"I guess because EF core library is included in .NET framework we should wait until then! That is awful, please consider put EF libraries out of .NET framework. Good ORM needs frequent release cycle."

Umm ... isn't that what the team said they were trying to do back in October?

Why, yes, replied Vega in a response to the two reader comments that were posted earlier this month:

"We have indeed looked at taking the whole of EF out of .NET Framework for this same reason. The June 2011 CTP of EF was a first attempt that showed us it is going to be harder than we thought because of the impact on existing applications, partner teams and ADO.NET provider writers."

You can read more about the long, strange trip to EF 5.0 here and bone up on coming EF 5.0 improvements here.

Besides improved SQL generation, the top five feature requests include "Batch CUD Support (1,179 votes); "EF Support for Second Level Cache" (655 votes); "Support for multiple databases" (595 votes); and "Entity Designer: Speed up & Optimize for using with 200+ entities" (524 votes).

What feature requests would you like to see in EF? Comment here or drop me a line.

Posted by David Ramel on 02/27/2012