bedrock-db

A simple, no deps Appen-only Database written in Zig 0.16.

Built without external dependencies, frameworks, or hidden allocations. Uses a Bitcask-style in-memory hash index for O(1) disk lookups.

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Features

• Written purely with Zig 0.16 STD Library
• Key offsets are indexed in a RAM Hash Map on startup, allowing direct single-read disk fetches on get().
• Keys in RAM live inside a dedicated Arena Allocator, which will clear all memory at once rather than in loops-- which can also cause memory fragmentation
• Deletes append a tombstone record to preserve append-only values while purging keys from RAM.
• A compact() routine will delete all extra unwanted rows.

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On-Disk Binary Format

Every record written to disk consists of a fixed 12-byte header followed by variable-length key and value byte payloads:

┌────────────┬──────────────────────┬──────────────┐
│ magic      │   key_len            │   value_len  │
│ 4 bytes    │   4 bytes            │   4 bytes    │
┼────────────┴──────────────────────┴──────────────┤
│                 key payload                      │
│                                                  │
┼──────────────────────────────────────────────────┼
│                 value payload                    │
└──────────────────────────────────────────────────┘

Struct Definition

const Header = extern struct {
    magic: [4]u8,   // Expected: "BDRK"
    key_len: u32,   // Length of key in bytes
    value_len: u32, // Length of value in bytes (0 for tombstones)
};

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Quick Start

Probably you can just download binary from the releases, but if the release does not work, clone and build!

git clone https://github.com/chishxd/bedrock-db.git && cd bedrock-db
zig build

# The binary should now be located in zig-out/bin
./zig-out/bin/bedrock-db

Example Commands

# Store a key-value pair
bedrock-db set user goku

# Update the key (appends new record to disk & updates RAM index)
bedrock-db set user ultra_instinct

# Retrieve the latest value (Instant O(1) jump!)
bedrock-db get user
# Output: [FOUND] user = ultra_instinct

# Delete a key (writes a tombstone to disk & removes from RAM index)
bedrock-db del user
# Output: [DELETED] Key 'user' removed

# Query a deleted key
bedrock-db get user
# Output: [NOT FOUND] Key 'user' does not exist

2. Inspect the Raw Bytes

xxd data-prod.db

You will see the raw BDRK header and your keys/values directly on disk.

3. Run Unit Tests

zig test src/db.zig
zig test src/main.zig

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Made with DETERMINATION by @Chish Licensed with MIT