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https://issues.apache.org/jira/browse/DERBY-3033?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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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)

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