private long getTxnCount() throws Exception {
    return TestTxnDbUtil.countQueryAgent(conf, "SELECT COUNT(*) FROM \"TXNS\"");
  }
Testing whether AcidTxnCleanerService removes the correct records
from the TXNS table (via TxnStore).
standalone-metastore/metastore-server/src/test/java/org/apache/hadoop/hive/metastore/txn/TestAcidTxnCleanerService.java