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https://issues.apache.org/jira/browse/DERBY-6726?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15537491#comment-15537491
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Bryan Pendleton commented on DERBY-6726:
----------------------------------------
Bernd, firstly, thank you VERY much for putting this energy into this issue!
Also, thank
you for the clear and detailed notes about your investigations, it is extremely
helpful.
I will try to find some time this weekend to replicate your findings in detail,
and to see
if I can add any additional clarity to your observations so far.
My instinct is that the initialization loop that you describe is not really a
hack, it is a
reasonable approach to correctly setting up the runtime data structures,
including
the table descriptors.
I agree with you that it is disturbing that "getTableDescriptor()" is the
routine that
gets used to initialize the table descriptor, although this sort of "initialize
upon first
reference" is not all that uncommon in the Derby codebase.
The other question is where, precisely, we want that initialization loop to be,
but as
a first guess, line 86 of TriggerEventActivator seems like a place to start.
As I said, I will try to find a few hours soon to dig through the code and
catch up
with your findings and give you some more feedback about whatever I might learn.
> 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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