What causes "cannot mark migration as completed: %w" in mattermost-community/focalboard?

Check the wrapped cause; if it is a connection timeout, increase idle/transaction timeouts and re-run.

cannot mark migration as completed

Error message

cannot mark migration as completed: %w

What it means

Error from SQLStore.RunUniqueIDsMigration (server/services/store/data_migrations.go:124). After replacing duplicate IDs, the migration marks completion by writing UniqueIDsMigrationKey=true via setSystemSetting(tx, ...). If that write fails, the transaction is rolled back (all ID replacements undone) and the error is wrapped as 'cannot mark migration as completed'.

Solutions

Check the wrapped cause; if it is a connection timeout, increase idle/transaction timeouts and re-run.
Ensure the DB user can INSERT/UPDATE the SystemSettings table.
Run the migration during a maintenance window so the transaction finishes quickly; the rollback makes retry safe (idempotent flag).
Avoid PgBouncer transaction-pooling misconfigurations that kill long transactions; use a dedicated session pool for migrations.
If 'Unique IDs transaction rollback error' also appears in logs, verify no manual cleanup is needed before retrying.

Example fix

// before
SET GLOBAL wait_timeout = 28800; -- default, too short for long txns
// after
SET GLOBAL wait_timeout = 86400;
SET GLOBAL max_allowed_packet = 64M;
-- then re-run: store.RunUniqueIDsMigration()

Defensive patterns

Strategy: retry

Validate before calling

var canWrite bool
if err := db.QueryRow("SELECT has_table_privilege('system_settings','INSERT','current_user')").Scan(&canWrite); err != nil || !canWrite { /* grant write before migrating */ }

Type guard

func isMigrationFinalizeError(err error) bool {
	return err != nil && strings.Contains(err.Error(), "cannot mark migration as completed")
}

Try / catch

err := store.RunUniqueIDsMigration()
if err != nil {
	if isMigrationFinalizeError(err) {
		// store already rolled back; fix timeouts/permissions and retry safely
		log.Println("migration rolled back, retryable:", errors.Unwrap(err))
	}
	return err
}

Prevention

Raise idle-transaction/timeout settings before long migrations
Use a direct DB connection (not transaction-pooled) for migrations
Grant the app user write access to SystemSettings
Run migrations single-instance to avoid settings-row contention

When it happens

Trigger: Running RunUniqueIDsMigration when the final setSystemSetting upsert into SystemSettings fails: connection loss, deadlock on the settings row, permissions failure, or settings table schema issues — after the (possibly lengthy) ID replacement work has already succeeded inside the transaction.

Common situations: Long-running migration holding the transaction open until the connection is dropped by a proxy/idle timeout (MySQL wait_timeout, PgBouncer) right before the final write; DB user lacking UPDATE rights on SystemSettings; concurrent migration runs contending on the settings row.

Related errors

AI-assisted analysis of mattermost-community/focalboard@a84bbb65e3 (2026-08-30). Data as JSON: /api/errors/048c8f9276ef3d17. Report an issue: GitHub.

Appendix: source

Thrown at server/services/store/sqlstore/data_migrations.go:124

				// do nothing for the first ID, only updating the others
				continue
			}

			newID := utils.NewID(model.BlockType2IDType(block.Type))
			if err := s.replaceBlockID(tx, block.ID, newID, block.WorkspaceID); err != nil {
				if rollbackErr := tx.Rollback(); rollbackErr != nil {
					s.logger.Error("Unique IDs transaction rollback error", mlog.Err(rollbackErr), mlog.String("methodName", "replaceBlockID"))
				}
				return fmt.Errorf("cannot replace blockID %s: %w", block.ID, err)
			}
		}
	}

	if err := s.setSystemSetting(tx, UniqueIDsMigrationKey, strconv.FormatBool(true)); err != nil {
		if rollbackErr := tx.Rollback(); rollbackErr != nil {
			s.logger.Error("Unique IDs transaction rollback error", mlog.Err(rollbackErr), mlog.String("methodName", "setSystemSetting"))
		}
		return fmt.Errorf("cannot mark migration as completed: %w", err)
	}

	if err := tx.Commit(); err != nil {
		return fmt.Errorf("cannot commit unique IDs transaction: %w", err)
	}

	s.logger.Debug("Unique IDs migration finished successfully")
	return nil
}

// RunCategoryUUIDIDMigration takes care of deriving the categories
// from the boards and its memberships. The name references UUID
// because of the preexisting purpose of this migration, and has been
// preserved for compatibility with already migrated instances.
func (s *SQLStore) RunCategoryUUIDIDMigration() error {
	setting, err := s.GetSystemSetting(CategoryUUIDIDMigrationKey)
	if err != nil {
		return fmt.Errorf("cannot get migration state: %w", err)

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