TxnHandler.enqueueLockWithRetry() - optimize sql

TxnHandler.enqueueLockWithRetry() does SQL insert into 2 tables using (possibly) multiple statements for each. Could easily generate 1 statement for each table.

TxnHandler.addDynamicPartitions() - the insert stmt here should combing multiple rows into single SQL stmt (but with a limit for extreme cases)

https://issues.apache.org/jira/browse/HIVE-13395?focusedCommentId=15271712&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15271712

In TxnHandler.commitTxn, would it make sense to rearrange this so that the check is made whether there are any operations that could conflict before the mutex is obtained and the transaction id checked? If there's nothing to record in the write sets I don't see why you need to hold the mutex or even record a commit txn id.

Note that Oracle doesn't support "insert into T values(1,2), (3,4)"