[HIVE-25203] HiveQueryResultSet and client operation are not expected to be closed twice

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-1
• Labels: pull-request-available
• Assignee: László Bodor
• Reporter: László Bodor
• Created: 06/Jun/21 03:04
• Updated: 17/Nov/22 08:47
• Resolved: 07/Jun/21 09:33

Description

While testing retry scenarios of HIVE-24786, we found that HiveQueryResultSet.close() is called twice, which is not expected. There are 2 different issues here:

1. ResultSet should not handle Statement as in HiveQueryResultSet:

    if (this.statement != null && (this.statement instanceof HiveStatement)) {
      HiveStatement s = (HiveStatement) this.statement;
      s.closeClientOperation();

The hiearchy of Connection(HiveConnection) -> Statement(HiveStatement) -> ResultSet(HiveQueryResultSet) should be respected in a sense that the parent can handle child but not the opposite way, only except a single case, where the state of the result set has an effect on statement's state, which is Statement.closeOnCompletion, which was introduced by HIVE-22698.
The above logic was introduced by HIVE-4974. Its intention was to make children able to return their parents, but that doesn't mean they should handle their parents' lifecycle.

2. Also, HiveStatement should close HiveQueryResultSet only if it's not already closed, so it would make sense to check ResultSet.isClosed() before closing. This is for the very same reason as another change above, to avoid duplicated close logic.

Background: under normal circumstances, a close operation is idempotent, we should not worry about any side effects of calling it twice, but while testing HIVE-24786, we found strange issues where in case of a SocketTimeoutException, such code path was hit in the jdbc client, that made HiveStatement.closeClientOperation() to be called twice, and it led to a WARNING on HS2 side. This is not expected as the operation close is protected by stmtHandle != null check, but yet it ran twice. To avoid situations like this, cleaning up duplicated close calls would help.

Issue Links

• is related to: HIVE-4974 JDBC2 statements and result sets are not able to return their parents
• is related to: HIVE-24786 JDBC HttpClient should retry for idempotent and unsent http methods
• is related to: HIVE-22698 Support Statement#closeOnCompletion()
• links to: GitHub Pull Request #2353