vitessio/vitess · error

error droppping database %q: %w

Error message

error droppping database %q: %w

What it means

During restore, cleanupMySQL drops all non-internal databases found on the target before the mysql-shell load. This error wraps a failure of the `DROP DATABASE IF EXISTS` super-query for a given database name.

Source

Thrown at go/vt/mysqlctl/mysqlshellbackupengine.go:629

func cleanupMySQL(ctx context.Context, params RestoreParams, shouldDeleteUsers bool) error {
	params.Logger.Infof("Cleaning up MySQL ahead of a restore")
	result, err := params.Mysqld.FetchSuperQuery(ctx, "SHOW DATABASES")
	if err != nil {
		return err
	}

	// drop all databases
	for _, row := range result.Rows {
		dbName := row[0].ToString()
		if slices.Contains(internalDBs, dbName) {
			continue // not dropping internal DBs
		}

		params.Logger.Infof("Dropping DB %q", dbName)
		err = params.Mysqld.ExecuteSuperQuery(ctx, fmt.Sprintf("DROP DATABASE IF EXISTS `%s`", row[0].ToString()))
		if err != nil {
			return fmt.Errorf("error droppping database %q: %w", row[0].ToString(), err)
		}
	}

	if shouldDeleteUsers {
		// get current user
		var currentUser string
		result, err = params.Mysqld.FetchSuperQuery(ctx, "SELECT user()")
		if err != nil {
			return fmt.Errorf("error fetching current user: %w", err)
		}

		for _, row := range result.Rows {
			currentUser = row[0].ToString()
		}

		// drop all users except reserved ones
		result, err = params.Mysqld.FetchSuperQuery(ctx, "SELECT user, host FROM mysql.user")
		if err != nil {

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Check the DBA user has DROP privileges and the server is not in super_read_only mode
2. Kill active connections holding the database open, then retry the restore
3. Inspect the wrapped inner error (%w) for the underlying MySQL error code and address it

// before restore: verify drop rights and read-only state
qr, err := mysqld.FetchSuperQuery(ctx, "SELECT @@read_only | @@super_read_only")
// expect 0; also ensure DBA user has DROP privilege

if _, err := engine.ExecuteRestore(ctx, params, backupDir); err != nil {
    var dbErr mysql.Err // or inspect the wrapped %w error
    if errors.As(err, &dbErr) {
        log.Error("restore cleanup failed dropping database", slog.Any("error", err))
    }
}

When it happens

Trigger: ExecuteRestore -> cleanupMySQL when params.Mysqld.ExecuteSuperQuery("DROP DATABASE IF EXISTS `name`") fails for one of the enumerated databases (returned by SHOW DATABASES filtering out internal DBs).

Common situations: Insufficient privileges (DROP not granted to the DBA user); database in use / locked by active connections; disk or replication issues; read-only mode (super_read_only) preventing DDL.

Related errors

• %w: "progressFile" needs to be empty as vitess always starts
• %w: "skipBinlog" needs to set to true
• %w: failed to fetch MySQL version: %v
• %w: failed to parse MySQL version (version: %s): %v
• %w: error checking if server supports disabling redo log: %v

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/d0699844545971ad. Report an issue: GitHub.