So everything was quite smooth, but with two exceptions:
- By some reason Project Upgrade Tool didn't process AssemblyInfo.cs file of model project - may be because the file was opened in VS.NET at the same time, so we occasionally overwritten the changes. In any case, that's easy to fix manually.
- Few of queries got broken. We're investigating this.
The main positive effect of migration is reduced startup time (~ 15%) and noticeably faster first time query executions - this happens because v4.3 doesn't use Reflection.Emit to build Tuples, but each complex query might utilize a set of them - they decribe intermediate results before abd after each operation in query plan.
Overall, we consider the result is very good. Just counted: there are 374 files containing [HierarchyRoot] attribute in model; at least 62 files contain EntitySet
fields, so there are > 400 tables in the database it uses, thus the count of different queries is simply huge.
Conclusion: if you're bound to .NET 3.5 or VS2008 usage, it's safe to migrate from v4.2 to v4.3 for .NET 3.5.