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https://issues.apache.org/jira/browse/DERBY-6726?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15536087#comment-15536087
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Bernd Ruehlicke edited comment on DERBY-6726 at 9/30/16 2:07 PM:
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I have tracked down the problem,
First I was comparing sources changes between 7.1.1 and 8.1.2 to reduce amount
of source to be checked and as I know it worked in 7.1.1. and failed in 8.1.2.
GenericTriggerExecutor, RowTriggerExecutor. TriggerEventActivator,
UpdateResultSet and GenericPreparedStatement where the same - so no problem
should be in those.
The problem happens in : iapi/sql/dictionary/TriggerDescriptor in the method
getActionSPS. (In 12.1.1. this is getSPS).
In 8.1.2 code was added to the method as part of DERBY-4874. When I comment out
this extra code in the 8.1.2 code base - the Test works ! I do not currently
understand what this extra code is doing, but it is for sure the culprit of the
problem.
Now looking at the 12.1.1 code we have the same or similar code in
TriggerDescriptor.getSPS(...). Again, commenting out the addition made for
DERBY-4874 and just have it do the same as back in the 7.1.1 days - the code
works also on 12.1.1
I will try to understand what the getSPS(..) is trying to do and why it falls
over having a double set of AFTER UPDATE triggers, but maybe someone closer to
the code can help with ideas as the problem is now pinned down to a few lines
of source.
I will now go into the 12.1.1 code base and try to understand the logic here
was (Author: bruehlicke):
I have tracked down the problem,
First I was comparing sources changes between 7.1.1 and 8.1.2 to reduce amount
of source to be checked and as I know it worked in 7.1.1. and failed in 8.1.2.
GenericTriggerExecutor, RowTriggerExecutor. TriggerEventActivator,
UpdateResultSet and GenericPreparedStatement where the same - so no problem
should be in those.
The problem happens in : iapi/sql/dictionary/TriggerDescriptor in the method
getActionSPS. (In 12.1.1. this is getSPS).
In 8.1.2 code was added to the method as part of DERBY-4874. When I comment out
this extra code in the 8.1.2 code base - the Test works ! I do not currently
understand what this extra code is doing, but it is for sure the culprit of the
problem.
Now looking at the 12.1.1 code we have the same or similar code in
TriggerDescriptor.getSPS(...). Again, commenting out the addition made for
DERBY-4874 and just have it do the same as back in the 7.1.1 days - the code
works also on 12.1.1
I will try to understand what the getSPS(..) is trying to do and why it falls
over having a double set of AFTER UPDATE triggers, but maybe someone closer to
the code can help with ideas as the problem is now pinned down to a few lines
of source.
I will now go into the 12.1.1 cod base and try to understand the logic here
> NPE from trigger
> ----------------
>
> Key: DERBY-6726
> URL: https://issues.apache.org/jira/browse/DERBY-6726
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.10.1.1
> Reporter: Tim Dudgeon
> Attachments: TriggerTest.diff, derbytrig.zip
>
>
> Saw this strange exception when doing an insert to a table with a trigger
> {code}
> Tue Sep 02 13:39:09 BST 2014 Thread[SQLExecution,1,system] (XID = 62693),
> (SESSIONID = 1), (DATABASE =
> C:/Users/timbo/Documents/IJCProjects/mini-regs/Vanilla
> Oracle/.config/derby-minireg-01-sep/db), (DRDAID = null), Failed Statement
> is: UPDATE samples SET sample_code = 'S123456' WHERE sample_id = CAST
> (org.apache.derby.iapi.db.Factory::getTriggerExecutionContext().getNewRow().getObject(1)
> AS INTEGER)
> java.lang.NullPointerException
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getTriggerActionString(Unknown
> Source)
> at
> org.apache.derby.iapi.sql.dictionary.TriggerDescriptor.getActionSPS(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.GenericTriggerExecutor.getAction(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.RowTriggerExecutor.fireTrigger(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.TriggerEventActivator.notifyEvent(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.UpdateResultSet.fireAfterTriggers(Unknown
> Source)
> at org.apache.derby.impl.sql.execute.UpdateResultSet.open(Unknown Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.executeStmt(Unknown
> Source)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.executeSubStatement(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.GenericTriggerExecutor.executeSPS(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.RowTriggerExecutor.fireTrigger(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.TriggerEventActivator.notifyEvent(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.InsertResultSet.normalInsertCore(Unknown
> Source)
> at org.apache.derby.impl.sql.execute.InsertResultSet.open(Unknown Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.executeStmt(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.EmbedStatement.execute(Unknown Source)
> at org.apache.derby.impl.jdbc.EmbedStatement.execute(Unknown Source)
> {code}
> The trigger definition is this:
> {code}
> CREATE TRIGGER samples_code_trg
> AFTER INSERT ON samples
> REFERENCING NEW AS newrow FOR EACH ROW MODE DB2SQL
> UPDATE samples SET sample_code = 'S123456'
> WHERE samples.sample_id = newrow.sample_id;
> {code}
> As mentioned here:
> http://mail-archives.apache.org/mod_mbox/db-derby-user/201408.mbox/%[email protected]%3E
> it could be that its caused by another AFTER UPDATE trigger that's on the
> table.
> Unfortunately I rebuilt all the tables and triggers and not the problem
> doesn't happen, so I can't provide a test case.
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