Memory usage

[willcosgrove]

Hi HTTP-2 community 👋

I'm writing this as a discussion, rather than an issue, because I'm not certain where my problem is. I've had a persistent memory leak in one of my running applications for at least a few months now and I've been sporadically trying to zero in on the problem.

It appears that I have several large Hash objects that are being held by HTTP2::Client.

This dump was taken from my app not very long after boot, so the actual size here is not that egregious, but I've been able to tell by taking a series of heap dumps that these are the objects that are growing over time.

So I started looking inside HTTP2::Client and HTTP2::Connection for possible culprits and I noticed @streams and @recently_closed_streams. It looks like there is a cleanup routine for @recently_closed_streams but I wasn't able to find where items are removed from @streams.

It seems like streams should eventually be removed from @streams, possibly when they're closed? I'm not familiar with the requirements of an HTTP2 client so I'm just guessing. Is this not a problem? Or maybe they are being removed and I just wasn't able to find where.

I'd appreciate any thoughts anyone has about the memory growth of those hashes. I should also say that I am using this as part of HTTPX which is using the Persistent plugin (via the Faraday adapter). It's being used to communicate to an Elasticsearch instance.

Thanks for your time!

[HoneyryderChuck]

fixed with #176.