Storage API

The storage module handles low-level file I/O, page management, and durability.

File I/O

const file = @import("file");

var f = try file.File.open("my.db");

Pager

Manages database pages in memory:

const pager = @import("pager");

var p = try pager.Pager.init(allocator, "my.db");

Write-Ahead Log (WAL)

Provides concurrent read/write access:

const wal = @import("wal");

var w = try wal.WAL.init("my.db");

Rollback Journal

Traditional durability mode:

const journal = @import("journal");

var j = try journal.Journal.init("my.db-journal");

SQLite Image

The on-disk format representation:

const sqlite_image = @import("sqlite_image");

var img = try sqlite_image.Image.init("my.db");

Page Format

Database pages follow the SQLite file format:

• Page 1: Database header (100 bytes) + schema table B-tree
• Table B-tree pages: Interior and leaf pages with cell pointers
• Index B-tree pages: Index data storage
• Freelist pages: Unused page tracking

Record Format

Records are encoded using SQLite's variable-length format:

• Header size (varint)
• Column types (serial types)
• Column data (text, integer, blob)

Varint Encoding

Variable-length integers for compact storage: