sqlite3/README.md

Go bindings to SQLite using Wazero

Go module github.com/ncruces/go-sqlite3 wraps a WASM build of SQLite, and uses wazero to provide cgo-free SQLite bindings.

• Package github.com/ncruces/go-sqlite3 wraps the C SQLite API (example usage).
• Package github.com/ncruces/go-sqlite3/driver provides a database/sql driver (example usage).
• Package github.com/ncruces/go-sqlite3/embed embeds a build of SQLite into your application.
• Package github.com/ncruces/go-sqlite3/vfs wraps the C SQLite VFS API and provides a pure Go implementation.
• Package github.com/ncruces/go-sqlite3/gormlite provides a GORM driver.

Caveats

This module replaces the SQLite OS Interface (aka VFS) with a pure Go implementation. This has benefits, but also comes with some drawbacks.

Write-Ahead Logging

Because WASM does not support shared memory, WAL support is limited.

To work around this limitation, SQLite is compiled with SQLITE_DEFAULT_LOCKING_MODE=1, making EXCLUSIVE the default locking mode. For non-WAL databases, NORMAL locking mode can be activated with PRAGMA locking_mode=NORMAL.

Because connection pooling is incompatible with EXCLUSIVE locking mode, the database/sql driver defaults to NORMAL locking mode. To open WAL databases, or use EXCLUSIVE locking mode, disable connection pooling by calling db.SetMaxOpenConns(1).

POSIX Advisory Locks

POSIX advisory locks, which SQLite uses, are broken by design.

On Linux, macOS and illumos, this module uses OFD locks to synchronize access to database files. OFD locks are fully compatible with process-associated POSIX advisory locks.

On BSD Unixes, this module uses BSD locks. BSD locks may not be compatible with process-associated POSIX advisory locks.

Testing

The pure Go VFS is tested by running an unmodified build of SQLite's mptest on Linux, macOS and Windows. Performance is tested by running speedtest1.

Roadmap

• advanced SQLite features
  • nested transactions
  • incremental BLOB I/O
  • online backup
  • session extension
• custom VFSes
  • custom VFS API
  • in-memory VFS
  • read-only VFS, wrapping an io.ReaderAt
  • cloud-based VFS, based on Cloud Backed SQLite
• custom SQL functions

Alternatives

• modernc.org/sqlite
• crawshaw.io/sqlite
• github.com/mattn/go-sqlite3
• github.com/zombiezen/go-sqlite