Deadlock?

[jswrenn]

To play around with this crate, I tried my hand at using it in mini-redis: jswrenn/mini-redis@a2ae42c. I launched my patched mini-redis with:

RUST_BACKTRACE=1 RUSTFLAGS="--cfg tokio_unstable" RUST_LOG=trace cargo run --bin mini-redis-server

...and, in another terminal, ran:

$ redis-benchmark -t set -n 1

Unfortunately, mini-redis then seems to deadlock before the benchmark can complete:

$ RUST_BACKTRACE=1 RUSTFLAGS="--cfg tokio_unstable" RUST_LOG=trace cargo run --bin mini-redis-server
    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
     Running `target/debug/mini-redis-server`
mini-redis-server::Handler::run                                                                                            18ms ├────────────────────────────┤
  run                                                                                                                      14ms ├──────────────────────┤
    read_frame                                                                                                            172μs ┆
    from_frame{frame: Array([Bulk(b"CONFIG"), Bulk(b"GET"), Bulk(b"save")])}                                               66μs  ┆
    apply{self: Unknown(Unknown { command_name: "config" }), db: Db { shared: Shared { state: Mutex { data: State { entr  432μs  │
      apply                                                                                                               254μs   ┆
    read_frame                                                                                                             95μs   ┆
    from_frame{frame: Array([Bulk(b"CONFIG"), Bulk(b"GET"), Bulk(b"appendonly")])}                                         55μs    ┆
    apply{self: Unknown(Unknown { command_name: "config" }), db: Db { shared: Shared { state: Mutex { data: State { entr 1015μs    ├┤
      apply                                                                                                               640μs    │
    read_frame                                                                                                            232μs               ┆

(At this point, I have to kill the mini-redis-server process in another terminal.)

Any thoughts about what might be going on here?

[rcoh]

I found two separate deadlock causes 😅 will get a new release out soon. Thanks for catching this!

[rcoh]

0.1.2 has been pushed. Also, thanks for that Redis example! It's the perfect test bed to quickly iterate on performance :-)

mini-redis-server::Handler::run                                                                                           143μs ├──────────────────────────────────────────────────────────────────────────────────────────────────────┤
  run                                                                                                                     138μs    ├──────────────────────────────────────────────────────────────────────────────────────────────────┤
    read_frame                                                                                                              7μs       ├───┤
    from_frame{frame: Array([Bulk(b"SET"), Bulk(b"key:__rand_int__"), Bulk(b"xxx")])}                                       2μs                      ├┤
    apply{self: Set(Set { key: "key:__rand_int__", value: b"xxx", expire: None }), db: Db { shared: Shared { state: Mute   40μs                                     ├───────────────────────────┤
      apply                                                                                                                35μs                                       ├────────────────────────┤
    read_frame                                                                                                             31μs                                                                       ├─────────────────────┤