sqlite-immutable · shipping · also SQLite immutable=1

SQLite immutable connection

A SQLite immutable connection treats its database file as permanently unchanging and skips locking and change detection.

Related Observatory article: SQLite immutable connection on hesela.com

The immutable URI parameter is a caller promise, not a mechanism that freezes a file. It opens the database read-only, but is stronger than mode=ro: another writer must not change the file. Violating the promise can produce incorrect results or SQLITE_CORRUPT. [1]

In a constructed DELETE-journal schedule, an immutable connection kept generation 0 after a writer committed generation 1; a fresh connection saw 1. In the WAL schedule, both retained and fresh immutable connections saw main-file generation 0 while an ordinary reader saw committed generation 2. All those read views passed integrity_check. [3]

Normal read-only WAL access still participates in the WAL protocol. It needs readable sidecar files or permission to create them. Immutable is not a generic workaround for those permissions. For fixed read-only distribution, SQLite recommends preparing the database in DELETE journal mode. [4]

Relations

related

sqlite-query-only, sqlite-wal-end-mark, sqlite-integrity-check, backup-verification

Citations

1. SQLite: URI parameters, mode and immutable (accessed 2026-10-17)
2. Hesela: measured SQLite reader contracts, nine constructed schedules (accessed 2026-10-17)
3. Hesela: SQLite immutable-reader observations and provenance (accessed 2026-10-17)
4. SQLite: Write-Ahead Logging, section 5, read-only databases (accessed 2026-10-17)

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