Toy database

A toy experiment to implement a persistent key value store with Rust.

Usage

Run the current repl with:

cargo run --release -- --repl

Run the server with... The server will start on localhost:5476. You can connect to it with nc

cargo run --release
nc localhost 5476

Run through stdin with:

cat commands.txt | cargo run --release -- --stdin

Features

Commands include:

• PUT key "value": Insert a key-value pair into the database
• GET key: Retrieve the value for a key
• DELETE key: Delete a key-value pair from the database
• EXIT: Close the database, ignored in stdin and server modes
• BEGIN: Start a transaction
• COMMIT: Commit a transaction
• ROLLBACK: Rollback a transaction

Testing and benching

Very primitive testing and benching is done in a separate repo here

TODOs:

• Implment a hash storage engine for the database
  • What performance impacts does this have? Turns out it's fast because I don't call fsync, but if I do, it slows down significantly
• Impelment a server client thingo so I can keep the database running whilst executing different commands from different connections against it
  • Make distinct modes in running the db, repl, stdin etc
  • Implement the tcp endpoint
• Implement a in memory WAL for the database
• Make it possible to close the database from the client tcp socket instead of ignoring the EXIT command
• Work on cleanup from signals
• Reimplmenet the legacy appendonly storage engine and modify it contain use the in memory WAL and the hash table as an index
• Clean up the code