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Bryan Pendleton updated DERBY-3033: ----------------------------------- Attachment: bug4736.sql Hi Kathey, thanks for the info about bug 4736. I took your pasted code and added 4 drop table statements to the front of it so I could run it repeatedly; it's attached as bug4736.sql. I ran that code repeatedly with my debugger set with a breakpoint in BaseActivation.getColumnFromRow() with a breakpoint set when row[rsNumber] was null (i.e., inside the "if" that you noted). Unfortunately, I never hit the breakpoint. I also tried removing that "if" statement from getColumnFromRow(), to see if the bug4736.sql would then provoke a NullPointerException, and that didn't happen either. So, whatever was going on with that "if" test, the bug4736.sql script no longer drives the conditions which cause row[rsNumber] to be null. I think you've got a good theory, though, and I'll continue to play with it, to try to understand that "if" statement in getColumnFromRow() better. > select query results in nullpointer exception in skipScan() > ----------------------------------------------------------- > > Key: DERBY-3033 > URL: https://issues.apache.org/jira/browse/DERBY-3033 > Project: Derby > Issue Type: Bug > Components: SQL > Affects Versions: 10.2.2.0 > Environment: Windows XP, Java 5.0, JDBC, Derby 10.2.2.0 > Reporter: Haolan Qin > Attachments: bug4736.sql, d3033-sane-ij-session-10.3.1.5.txt, > query_plan.new, query_plan.old, test.rar, test.zip, viewer_10_1.zip > > > The following error was repeatedly thrown when we tried to run a select query > via JDBC. Strangely, the exact same select query did not trigger any error > when run from the command line console. After we added an index, the error > went away completely. > java.lang.NullPointerException > at org.apache.derby.impl.sql.execute.NoPutResultSetImpl.skipScan(Unknown > Source) > at org.apache.derby.impl.sql.execute.TableScanResultSet.openCore(Unknown > Source) > at > org.apache.derby.impl.sql.execute.IndexRowToBaseRowResultSet.openCore(Unknown > Source) > at > org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.openCore(Unknown > Source) > at org.apache.derby.impl.sql.execute.JoinResultSet.openRight(Unknown Source) > at org.apache.derby.impl.sql.execute.JoinResultSet.openCore(Unknown Source) > at > org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.openCore(Unknown > Source) > at org.apache.derby.impl.sql.execute.SortResultSet.openCore(Unknown Source) > at > org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.openCore(Unknown > Source) > at org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.open(Unknown > Source) > at org.apache.derby.impl.sql.GenericPreparedStatement.execute(Unknown Source) > at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(Unknown Source) > at > org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(Unknown > Source) > at org.apache.derby.impl.jdbc.EmbedPreparedStatement.execute(Unknown Source) > at org.apache.derby.impl.drda.DRDAStatement.execute(Unknown Source) > at org.apache.derby.impl.drda.DRDAConnThread.processCommands(Unknown Source) > at org.apache.derby.impl.drda.DRDAConnThread.run(Unknown Source) -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.