presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/metadata/ShardCleaner.java/ShardCleaner/deleteOldCompletedTransactions
class ShardCleaner:    @VisibleForTesting
    void deleteOldCompletedTransactions()
    {
        while (!Thread.currentThread().isInterrupted()) {
            int deleted = dao.deleteOldCompletedTransactions(maxTimestamp(maxCompletedTransactionAge));
            if (deleted < CLEANUP_TRANSACTIONS_BATCH_SIZE) {
                break;
            }
        }
    }