High memory consumption after update from 0.16 to 0.18

[ok-ul-ch]

Summary

After the update to 0.18, we've started to observe weird memory behavior in our app, which looks like a memory leak to me.

I've used code from examples/examples/tokio_console.rs to reproduce the issue, it starts jsonrpsee server, registers dummy method and waits. Client sends requests sequentially and receives 405 Status Code.

Server code

use std::net::SocketAddr;

use jsonrpsee::server::ServerBuilder;
use jsonrpsee::RpcModule;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
	let _ = run_server().await?;

	futures::future::pending().await
}

async fn run_server() -> anyhow::Result<SocketAddr> {
	let server = ServerBuilder::default().build("127.0.0.1:9944").await?;
	let mut module = RpcModule::new(());

	//Use for 0.18
	//module.register_method("say_hello", |_, _| "lo")?;
	module.register_method("say_hello", |_, _| Ok("lo"))?;

	let addr = server.local_addr()?;
	let handle = server.start(module)?;

	// In this example we don't care about doing a stopping the server so let it run forever.
	// You may use the `ServerHandle` to shut it down or manage it yourself.
	tokio::spawn(handle.stopped());

	Ok(addr)
}

Client code

use std::time::Duration;

#[tokio::main]
async fn main() {
    tokio::spawn(async {
        loop {
            let _ = dbg!(reqwest::get("http://127.0.01:9944").await);

            tokio::time::sleep(Duration::from_millis(10)).await
        }
    });

    futures::future::pending().await
}

STR

1. Run server code sample for both: 0.16.2 and 0.18.2 versions of jsonrpsee;
2. Run client;
3. Observe memory usage.

Behavior

0.16.2 - memory usage is constant, as expected. See heaptrack profile report

0.18.2 - memory usage grows over time. See heaptrack profile report

[ok-ul-ch]

It looks like the issue is in the fact that futures running connections are not dropped.
Connections are inserted here and here BUT not removed in the server's loop here

Flamegraph reporting "leak"

[aoudiamoncef]

Hi @mralexes, have you tested with max_connections = 1 ? (to see the result)

[ok-ul-ch]

@aoudiamoncef yup, same behavior