[HIVE-15999] Fix flakiness in TestDbTxnManager2

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Fix Version/s: 2.2.0
• Component/s: Tests, Transactions
• Target Version/s: 2.2.0
• Assignee: Wei Zheng
• Reporter: Wei Zheng
• Created: 21/Feb/17 22:05
• Updated: 25/Jul/17 20:05
• Resolved: 24/Feb/17 19:08

Description

Right now there is test flakiness wrt. TestDbTxnManager2. The error is like this:

java.sql.SQLException: Table/View 'TXNS' already exists in Schema 'APP'.
	at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown Source)
	at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown Source)
	at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown Source)
	at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(Unknown Source)
	at org.apache.derby.impl.jdbc.EmbedStatement.execute(Unknown Source)
	at org.apache.derby.impl.jdbc.EmbedStatement.execute(Unknown Source)
	at org.apache.hadoop.hive.metastore.txn.TxnDbUtil.prepDb(TxnDbUtil.java:75)
	at org.apache.hadoop.hive.ql.lockmgr.TestDbTxnManager2.setUp(TestDbTxnManager2.java:90)

The failure is due to HiveConf used in the test being polluted by some test, e.g. in testDummyTxnManagerOnAcidTable(), conf entry HIVE_TXN_MANAGER is set to "org.apache.hadoop.hive.ql.lockmgr.DummyTxnManager" but not switched back.