[HIVE-17647] DDLTask.generateAddMmTasks(Table tbl) and other random code should not start transactions

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Transactions
• Labels: mm-gap-2
• Assignee: Sergey Shelukhin
• Reporter: Eugene Koifman
• Created: 29/Sep/17 01:30
• Updated: 22/May/18 23:13
• Resolved: 23/Apr/18 18:14

Description

This method (and other places) have

      if (txnManager.isTxnOpen()) {
        mmWriteId = txnManager.getCurrentTxnId();
      } else {
        mmWriteId = txnManager.openTxn(new Context(conf), conf.getUser());
        txnManager.commitTxn();
      }

this should throw if there is no open transaction. It should never open one.

In general the logic seems suspect. Looks like the intent is to move all existing files into a delta_x_x/ when a plain table is converted to MM table. This seems like something that needs to be done from under an Exclusive lock to prevent concurrent Insert operations writing data under table/partition root. But this is too late to acquire locks which should be done from the Driver.acquireLocks() (or else have deadlock detector since acquiring them here would bread all-or-nothing lock acquisition semantics currently required w/o deadlock detector)

Issue Links

• is duplicated by: HIVE-16850 Converting table to insert-only acid may open a txn in an inappropriate place
• links to: RB