tursodatabase/turso · error · Error

not implemented

Error message

not implemented

What it means

Database.backup() is a stub in the Turso better-sqlite3 compatibility layer. The method exists so that better-sqlite3 code parses, but calling it always throws 'not implemented' because the underlying online-backup API has not been wired up to the Turso engine yet.

Source

Thrown at bindings/javascript/packages/common/compat.ts:230

    if (typeof source !== "string")
      throw new TypeError("Expected first argument to be a string");

    if (typeof options !== "object")
      throw new TypeError("Expected second argument to be an options object");

    const pragma = `PRAGMA ${source}`;

    const stmt = this.prepare(pragma);
    try {
      const results = stmt.all();
      return results;
    } finally {
      stmt.close();
    }
  }

  backup(filename, options) {
    throw new Error("not implemented");
  }

  serialize(options) {
    throw new Error("not implemented");
  }

  function(name, options, fn) {
    throw new Error("not implemented");
  }

  aggregate(name, options) {
    throw new Error("not implemented");
  }

  table(name, factory) {
    throw new Error("not implemented");
  }

View on GitHub (pinned to bad083fafb)

Solutions

1. Replace backup() with SQL: run db.exec("VACUUM INTO '/path/to/file.db'") to produce a consistent snapshot file
2. Or copy the database file when no connection has it open (after close())
3. Feature-detect before calling: if (db.backup.toString().includes('not implemented')) fallback
4. Track/await upstream support for the backup API in the Turso bindings

Example fix

// before
db.backup('/tmp/backup.db'); // throws not implemented

// after
db.exec("VACUUM INTO '/tmp/backup.db'");

const supportsBackup = !db.backup.toString().includes('not implemented');
if (supportsBackup) db.backup(dest);
else db.exec(`VACUUM INTO '${dest}'`);

function supportsDbBackup(db: Database): boolean {
  try {
    return !/not implemented/.test(String(db.backup));
  } catch {
    return false;
  }
}

try {
  db.backup(dest);
} catch (err) {
  if (err instanceof Error && err.message === 'not implemented') {
    db.exec(`VACUUM INTO '${dest}'`); // consistent snapshot via SQL
  } else {
    throw err;
  }
}

When it happens

Trigger: Calling db.backup('/path/to/file.db') directly; running better-sqlite3 application code unmodified against the Turso bindings; test suites or migration scripts that snapshot the database via backup().

Common situations: Porting an existing better-sqlite3 project to Turso; CI pipelines that create a backup copy of the database file before running destructive tests; tools that periodically back up the live database.

Related errors

• The database connection is not open
• The supplied SQL string contains no statements
• Expected first argument to be a function
• Expected first argument to be a string
• Expected second argument to be an options object

AI-assisted analysis of tursodatabase/turso@bad083fafb (2026-08-16). Data as JSON: /api/errors/cc56e0e31e8bdf02. Report an issue: GitHub.