severe memory leak in new version

[smasherprog]

We upgraded to the latest version 1.3.0 and have found a serious memory leak issue.

I have attached a screenshot of a memory dump of our website which was affected by this

This is what is inside of the networkchange handler

We use the latest version of MongoDB.Driver 2.10.2 in our application which uses this library.

As you can see from the memory dumps, it looks like the dnscache is filling up with too many entries. This causes our application to slowly become unresponsive. My guess is that looking through the 100k entries in the dnscache is a slow.

I am unsure why this occurs or how to reproduce it as it seemed to occur randomly. Let me know of anything I can do to help as we are now stuck using 1.2.0 hoping that it doesn't break our site (we have been getting bit by this #55) and 1.3.0 which causes random site unresponsiveness.

[MichaCo]

I shouldn't add new features while sick it seems -.-
Didn't thought about the bad behavior of events which basically keep the reference alive forever.

The memory footprint should be zero after creating an instance of LookupClient and not keeping any references, so this is clearly a bug which I will fix.

I'd have to make the LookupClient IDisposable to make it unsubscribe properly though, and I don't want to do that... therefore I'll remove that feature.

Thanks for figuring that out and letting me know! 👍

That being said, that's an absurd amount of instances of LookupClient.
Does that mean the MogoDB.Driver creates a new instance every time you call it or something?
That would be pretty unfortunate because there is some performance overhead instantiating the client with auto-nameserver discovery (it has to query network interfaces and such which will take a couple milliseconds)..
And caching is basically disabled if the instance isn't kept / reused.

[MichaCo]

Should be fixed in https://github.com/MichaCo/DnsClient.NET/releases/tag/1.3.1 which was just pushed to Nuget.

Let me know if you still see any issues or if it works.

[smasherprog]

Awesome we will take a look and see if this fixes the issue. Thanks for the quick response!

[DmitryLukyanov]

Does that mean the MogoDB.Driver creates a new instance every time you call it or something?

yep, we do it each time when we need to resolve a connection string. This is a ticket to solve it: https://jira.mongodb.org/browse/CSHARP-3038

@smasherprog , please let us know whether updating to a new package version solved your issue.

[smasherprog]

The new version did fix our memory and slowness issue. We are running it on our production environment and its working!
The Mongo driver should up its version requirement for sure!

[MichaCo]

Thanks @smasherprog for the confirmation!