Differences in generated SQL - Local to Production Server - entity-framework-4

Question

Our SQL DBA has pointed out that EF is generating some SQL that is causing implicit conversion and is leading to some performance problems. When I run the web application locally, I see a different query than the stage/production servers are generating. I am assuming that there are EF differences between my dev box and the server and need help determining where to look. I have verified the queries in SQL Profiler.
Local: Windows 7, 64-bit, IIS 7
Servers: Windows Server 2003, 32-bit, IIS 6
Linq statement (incoming is a List of type string):
var result = from i in context.ProductImages
where incoming.Contains(i.productID)
select i;
var sql = ((System.Data.Objects.ObjectQuery)result).ToTraceString();
return result.ToList();
Local generated query:
SELECT [Extent1].[column1],
[Extent1].[column2],
..rest of columns...
WHERE [Extent1].[productID] IN ('000176725','000176726','000176728')
Server generated query:
SELECT [Extent1].[column1],
[Extent1].[column2],
..rest of columns...
WHERE [Extent1].[productID] IN (N'000176725',N'000176726',N'000176728')
Any ideas on where to investigate to determine what is causing the generation difference? the "N'" is causing the performance challenge.
As far as I can tell, the System.Data.Entity dll is the same version (4.0.30319.1)

Answer 1

Looks like your server runs actual .NET Framework 4 while on your box you have .NET Framework 4.5. (note that the version of System.Data.Entity.dll will be the same). There was a bug in EF which was fixed in EF5/.NET Framework 4.5 and since .NET Framework 4.5 was an in-place update the fix is automatically picked up by apps that are using EF4 on boxes that have .NET Framework 4.5 installed.
You can change your app to work around the bug as described here.