MKDB

Toy database implemented for learning purposes. Almost all of the implementation ideas come from these resources:

• SQLite 2.8.1 source code
• CMU Intro to Database Systems 2023
• CMU Intro to Database Systems 2018

Other less important resources are linked in the source code.

Compilation

Install rustup if you don't have it and then install the nightly toolchain:

rustup toolchain install nightly

Use cargo to compile the project:

cargo +nightly build

Alternatively, set your default toolchain to nightly to avoid specifying +nightly for every cargo command:

rustup default nightly

Compiler Version

If you see any compilation errors it's probably because of the compiler version. Run rustc +nightly --version and compare the output to the last version used to compile and test the project:

rustc 1.78.0-nightly (9c3ad802d 2024-03-07)

Tests

Use cargo test to run all the unit tests:

cargo +nightly test

Unsafe

All the unsafe code is located in ./src/storage/page.rs, which is the module that implements slotted pages. Miri can be used to test possible undefined behaviour bugs. Install the component using rustup:

rustup +nightly component add miri

Then use cargo to test the page module:

cargo +nightly miri test storage::page::tests

The ./src/paging/ and ./src/storage/btree.rs modules are not unsafe themselves but they heavily rely on the slotted page module so it's worth testing them with Miri as well:

cargo +nightly miri test paging
cargo +nightly miri test storage::btree

If all these modules work correctly without UB then the rest of the codebase should be fine. The ultimate UB test is the ./src/db.rs module since it's the entry point to SQL execution so it makes use of every other module. It can be tested with Miri as well since tests are configured to run completely in memory without files or system calls:

cargo +nightly miri test db::tests

The rest of modules don't make any use of unsafe code so it's not necessary to test them with Miri.

Running The Program

Use this command to start the TCP server on port 8000 (the default if not specified):

cargo +nightly run -- file.db 8000

file.db can be any empty file or a file previously managed by mkdb. It works like SQLite in that regard, the difference is that in order to use mkdb you have to connect to the server with some TCP client that implements the network protocol described at ./src/tcp/proto.rs. The ./client package is a console client similar to that of MySQL or any other database and can be used like this:

cargo +nightly run --package client -- 8000

This will connect to the mkdb server running on port 8000 and provide you with a shell where you can type SQL and see the results of the queries.