Massive performance hit when upgrading from 1.0.8.18 to 1.0.9

[ascott18]

We have a bit of code that, in this example, ends up calling .OrderBy("SomeProperty ASC, SomeOtherProp DESC") a total of 262 times, each time on an EnumerableQuery<T> (that is, LINQ to objects rather than LINQ to sql).

With 1.0.8.18, the total CPU time spent in System.Linq.Dynamic.Core.DynamicQueryableExtensions::OrderBy was ~58ms. In 1.0.9, the total CPU time for the same code against the same data is ~17691ms:

It appears that System.Linq.Dynamic.Core is iterating over every single type currently loaded into the app domain, and pulling the custom attributes from every one of those types? Why is it doing this? Why does it do this on every single call to OrderBy()?

[StefH]

1. Are you using NET Full framework (4.x ?) or NETStandard/NetCore ?
2. And do you have set AllowNewToEvaluateAnyType to true or false in the config?

[StefH]

#237

[StefH]

@ascott18
Can you try MyGet package:
https://www.myget.org/feed/system-linq-dynamic-core/package/nuget/System.Linq.Dynamic.Core/1.0.9.1-ci-1643 ? This should hopefully fix your issue.

[ascott18]

This was with net471, and all config is default.

Thanks for the fix - I won't have a chance to try it out for a while, though.

[StefH]

@ascott18 When do you have time to validate?

[ascott18]

Its an order of magnitude better than 1.0.9, but still ~2 orders of magnitude worse than it was in 1.0.8.18, to the extent that it will still be unusable for our use cases:

[StefH]

How did you do that exact profiling?

[ascott18]

In VS 2017 preview:

• Start my application in debug

• Put a breakpoint before and after my code that is doing all the calls to OrderBy

• When the breakpoint before is hit, turn on "Record CPU Profile" in the Diagnostic Tools window, and then continue
  

• When the second breakpoint is hit, the CPU profile results will be analyzed and displayed.

• Scroll down in the CPU profile results to the lines for OrderBy. Right-click one of the OrderBy lines, and choose something like "display in call tree" (can't remember exactly what it says).

[StefH]

I found the issue, the types were not cached anymore. I added the caching again, this should be fixed in MyGet version 1.0.9.1-ci-1661. Can you please test this?

[ascott18]

Thanks - that fixed it completely!

[StefH]

Official version 1.0.9.1 will be released in some time.