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https://issues.apache.org/jira/browse/DERBY-4538?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12839645#action_12839645
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Knut Anders Hatlen commented on DERBY-4538:
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v2 looks like a good incremental improvement. +1 to commit.

(Nit: The declarations of needToIncludeAllColumns end with two semi-colons.)

> If the CREATE TRIGGER does not have the REFERENCING clause, then there is no 
> need to keep before and after values for the triggering table
> ------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-4538
>                 URL: https://issues.apache.org/jira/browse/DERBY-4538
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.6.0.0
>            Reporter: Mamta A. Satoor
>            Assignee: Mamta A. Satoor
>            Priority: Minor
>         Attachments: DERBY4538_NoReferencingClause_diff_v1.txt, 
> DERBY4538_NoReferencingClause_diff_v2.txt, 
> DERBY4538_NoReferencingClause_stat_v1.txt, 
> DERBY4538_NoReferencingClause_stat_v2.txt
>
>
> In order for the trigger action to have access to before and after values of 
> the triggering table, the CREATE TRIGGER should use the REFERENCING clause. 
> Without the REFERENCING clause, old and new values of triggering table can't 
> be accessed by the trigger action. Based on this, we can improve Derby memory 
> utilization by not keeping old and new values if REFERENCING clause is 
> missing. It will be good to see if the code already does this optimization 
> and if not, then introducing this optimization will definitely be very useful 
> when the triggering table could have LOB columns.

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