Channel Lag issue

[CR7273868]

Fred version - 9.1.2 - REPLICAS Features enabled Redis version - 7.2.5 JEMALLOC Platform - LINUX Debian Bullseye Deployment type - cluster

My cluster setup consists of 4 servers. Each 3 masters and to each master 1 slave.

12 masters - 12 slaves in total.

Describe the bug Not sure if it's a bug, but I think it is redis-cli doesn't suffer from this. Fred does. After a while it says Error channel lagged by 5559. This comes from using the RX.

To Reproduce Steps to reproduce the behavior: Just heavily fast send to a channel and wait a couple of seconds

Following code:

use fred::{
    prelude::{ClientLike, EventInterface, PubsubInterface, RedisClient},
    types::RedisConfig,
};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let config = RedisConfig::from_url("redis-cluster://masked:7002?node=masked:7002&node=masked:7005&node=masked:7008&node=masked:7011")?;
    let client = RedisClient::new(config, None, None, None);
    client.init().await?;

    client.ssubscribe("channel").await?;
    let mut rx = client.message_rx();
    loop {
        let message = rx.recv().await?;
        println!("Message: {:?}", message);
    }
    Ok(())
}

Should get an error like this:

Logs

Error: channel lagged by 5559

(If possible set RUST_LOG=fred=trace and run with --features debug-ids)

[aembke]

Hi @CR7273868,

That's an indication that the broadcast channel is receiving messages faster than they're being processed on the receiving end. You can change the buffer size of the broadcast channels with the broadcast_channel_capacity configuration option like this:

https://github.com/aembke/fred.rs/blob/f798232966ff6ee75ad60c09f42bef67f440a9ed/examples/misc.rs#L16-L17

The default is 32, so you'll probably want to increase that quite a bit.