Use a serialization library

[arenadotio]

Use a serialization library

[brendanlong]

I did some experimentation with Angstrom and my basic parser was an order of magnitude slower than Pgx's current code. I might try a little bit more experimentation with flambda. It's also awkward to write since OCaml doesn't have unsigned types, so we either need to use the integers library, which uses C code and is significantly slower, or pass around uint32's as int64's 🤮

[brendanlong]

We should probably look into how PG'OCaml and Postgres_async do serialization and see if we can come up with a base parser/serializer library that they could both theoretically use too.

[brendanlong]

Nevermind, it looks like if we add Async overhead into account, Angstrom_async actually reads data more efficiently than Pgx does, which massively swamps the difference in parse speed:

Estimated testing time 14s (14 benchmarks x 1s). Change using '-quota'.
┌─────────────────────────────────────────────────────────┬────────────┬─────────┬──────────┬──────────┬────────────┐
│ Name                                                    │   Time/Run │ mWd/Run │ mjWd/Run │ Prom/Run │ Percentage │
├─────────────────────────────────────────────────────────┼────────────┼─────────┼──────────┼──────────┼────────────┤
│ Authentication_ok.parse (string)                        │   441.74ns │ 281.26w │          │          │     10.68% │
│ Authentication_ok.parse (bigstring)                     │   403.78ns │ 272.24w │          │          │      9.77% │
│ Authentication_ok_int.parse (string)                    │   190.38ns │ 221.11w │          │          │      4.60% │
│ Authentication_ok_int.parse (bigstring)                 │   123.72ns │ 212.07w │          │          │      2.99% │
│ Authentication_ok_int_lift.parse (string)               │   158.35ns │ 155.09w │          │          │      3.83% │
│ Authentication_ok_int_lift.parse (bigstring)            │    93.14ns │ 146.00w │          │          │      2.25% │
│ Authentication_ok_int_lift.parse (unbuffered bigstring) │    96.23ns │ 169.00w │          │          │      2.33% │
│ Authentication_ok_int_lift.parse (async)                │ 3_497.32ns │ 678.75w │    0.35w │    0.35w │     84.59% │
│ Authentication_ok_int64.parse (string)                  │   205.84ns │ 251.00w │          │          │      4.98% │
│ Authentication_ok_int64.parse (bigstring)               │   146.00ns │ 242.00w │          │          │      3.53% │
│ Authentication_ok_int_simple.parse (string)             │   183.80ns │ 211.00w │          │          │      4.45% │
│ Authentication_ok_int_simple.parse (bigstring)          │   122.37ns │ 202.00w │          │          │      2.96% │
│ Pgx                                                     │    23.40ns │  22.00w │          │          │      0.57% │
│ Pgx_async                                               │ 4_134.51ns │ 639.19w │    0.29w │    0.29w │    100.00% │
└─────────────────────────────────────────────────────────┴────────────┴─────────┴──────────┴──────────┴────────────┘

I'll clean this up and put up a basic repo sometime soon.

[brendanlong]

I started working on this here: https://github.com/brendanlong/ocaml-postgres-protocol