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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DERBY-2698) caching collation elements in WorkHorseForCollatorDatatypes may improve performance.
Date Tue, 02 Oct 2012 05:19:07 GMT

     [ https://issues.apache.org/jira/browse/DERBY-2698?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Mamta A. Satoor updated DERBY-2698:
-----------------------------------

    Urgency: Normal
     Labels: derby_triage10_10  (was: )
    
> caching collation elements in WorkHorseForCollatorDatatypes may improve performance.
> ------------------------------------------------------------------------------------
>
>                 Key: DERBY-2698
>                 URL: https://issues.apache.org/jira/browse/DERBY-2698
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.3.1.4
>            Reporter: Mike Matrigali
>            Priority: Minor
>              Labels: derby_triage10_10
>
> In java/engine/org/apache/derby/iapi/types/WorkHorseForCollatorDatatypes.getCollationElementsForString()
an array
> of int's is calculated given the string and the collator in place.  If like is ever called
on the same DataValueDescriptor, caching
> this calculation will be faster than redoing the calculation.  To make this change one
needs to properly invalidate the cached
> information when the base type value is changed.  For instance in the case of SQLChar()
the following routines all result
> in a change in the value of the datatype and thus need to invalidate any cached collation
element structure:
> readExternalFromArray()
> readExternal()
> setValue()
> there may be others.
> DERBY-2670 is an example of what can go wrong if you get the caching wrong.

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