benbjohnson/litestream · error

cannot determine current position: %w

Error message

cannot determine current position: %w

What it means

This error wraps a failure from r.db.Pos(), which reads the database's current replication position (TXID/page) from the local SQLite database header and WAL. Litestream needs the current position in syncOnce to compute which LTX frames still need uploading; if reading that position fails, the sync cannot proceed and the underlying cause is wrapped so the real error is preserved.

Source

Thrown at replica.go:195

	}()

	if err := ctx.Err(); err != nil {
		return result, context.Cause(ctx)
	}

	// Calculate current replica position, if unknown.
	if r.Pos().IsZero() {
		pos, err := r.calcPos(ctx)
		if err != nil {
			return result, fmt.Errorf("calc pos: %w", err)
		}
		r.SetPos(pos)
	}

	// Find current position of database.
	dpos, err := r.db.Pos()
	if err != nil {
		return result, fmt.Errorf("cannot determine current position: %w", err)
	} else if dpos.IsZero() {
		return result, errReplicaWaitForData
	}

	r.Logger().Debug("replica sync",
		slog.Group("txid",
			slog.String("replica", r.Pos().TXID.String()),
			slog.String("db", dpos.TXID.String()),
		))

	// Replicate all L0 LTX files since last replica position.
	for txID, syncedFileN := r.Pos().TXID+1, 0; txID <= dpos.TXID; txID = r.Pos().TXID + 1 {
		if maxSyncLTXFiles > 0 && syncedFileN >= maxSyncLTXFiles {
			result.limited = true
			// Uploads succeeded, so record sync health; otherwise a
			// sustained backlog reads as unhealthy while progressing.
			r.db.RecordSuccessfulSync()
			r.Logger().Debug("replica sync limited",

View on GitHub (pinned to 4ed7a308f6)

Solutions

1. Check the wrapped cause (%w) to see the underlying db.Pos() error and fix that (missing file, permissions, corruption).
2. Verify the database path in config still exists and litestream has read/write access to the DB, WAL, and SHM files.
3. Restart litestream so the DB handle is re-opened against the current database file.
4. If local LTX/DB state is corrupted, run `litestream reset` for the database before resuming replication.

// before syncing, confirm the DB is open and files are readable
if _, err := os.Stat(dbPath + "-wal"); err != nil {
    return fmt.Errorf("db wal unreadable: %w", err)
}
pos, err := db.Pos()
if err != nil || pos.IsZero() {
    return fmt.Errorf("db not ready for sync: %w", err)
}

if err := replica.Sync(ctx); err != nil {
    var wrapped interface{ Unwrap() error }
    if errors.As(err, &cause) && strings.Contains(err.Error(), "cannot determine current position") {
        log.Printf("db position unreadable, resetting local state: %v", cause)
    }
}

When it happens

Trigger: Replica.syncOnce (or sync) runs while the underlying DB handle cannot read its position — e.g. the database file was deleted/moved, the DB is not open, WAL/SHM files are unreadable, or the db metadata read returns an I/O or SQLite error. Callers: TestReplica_SyncOnceLimitsLTXFiles and Replica.sync.

Common situations: Database file removed or corrupted while litestream is running; DB closed concurrently; running on a filesystem where the WAL/SHM can't be read (permissions, NFS issues); pointing a replica at a database path that no longer exists.

Understand the failure class

Background: Database query failed: Internal Server Error 500s wrapping SQL, Prisma, and connection failures — what to check first — this error's family across 16 libraries.

Related errors

• replica required before opening database
• replica client required before opening database
• cannot copy wal before checkpoint: %w
• cannot copy wal after passive checkpoint: %w
• cannot copy wal after checkpoint: %w

AI-assisted analysis of benbjohnson/litestream@4ed7a308f6 (2026-09-06). Data as JSON: /api/errors/7d378206c9457170. Report an issue: GitHub.