[jira] [Commented] (NIFI-5070) java.sql.SQLException: ERROR 1101 (XCL01): ResultSet is closed

["Matt Burgess (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/NIFI-5070?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16433070#comment-16433070 ] 

Matt Burgess commented on NIFI-5070:
------------------------------------

The spec doesn't quite say that a SQLException can be thrown when there are no more rows, rather it implies that next() should first return false, then can throw an exception (such as other ResultSet methods that require a current row after next() returns false).  I believe DB2 does throw a SQLException instead of returning false when there are no more rows, I'm not sure if Phoenix does this or not.

I'd like to avoid calling isClosed() before next() as for a large number of rows X, we'd be calling it unnecessarily X-1 times. Having said that, if something happens during processing and the driver/DB closes the result set as a result of that error, we wouldn't know (with a single try/catch) whether the result set had finished or had an error somewhere.  I think we'd need a try/catch around the next() only to see if the result set is closed, and an inner try/catch around everything else, to catch other errors not related to this behavior. [~markap14] I think you're the one that mentioned not calling isClosed() every time, any thoughts on this?

> java.sql.SQLException: ERROR 1101 (XCL01): ResultSet is closed
> --------------------------------------------------------------
>
>                 Key: NIFI-5070
>                 URL: https://issues.apache.org/jira/browse/NIFI-5070
>             Project: Apache NiFi
>          Issue Type: Bug
>          Components: Core Framework
>    Affects Versions: 1.6.0
>            Reporter: Gardella Juan Pablo
>            Priority: Major
>
> Discovered during NIFI-5049. According [ResultSet.next() javadoc|https://docs.oracle.com/javase/8/docs/api/java/sql/ResultSet.html#next%E2%80%93]:
> _When a call to the {{next}} method returns {{false}}, the cursor is positioned after the last row. Any invocation of a {{ResultSet}} method which requires a current row will result in a {{SQLException}} being thrown. If the result set type is {{TYPE_FORWARD_ONLY}}, it is vendor specified whether their JDBC driver implementation will return {{false}} or throw an {{SQLException}} on a subsequent call to {{next}}._
> With Phoenix Database and QueryDatabaseTable the exception {{java.sql.SQLException: ERROR 1101 (XCL01): ResultSet is closed}} is raised.
>  
>  



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)