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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DERBY-2721) improve performance of index lookups of string types in territory based collated databases.
Date Tue, 02 Oct 2012 05:05:08 GMT

     [ https://issues.apache.org/jira/browse/DERBY-2721?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Mamta A. Satoor updated DERBY-2721:
-----------------------------------

    Urgency: Normal
     Labels: derby_triage10_10  (was: )
    
> improve performance of index lookups of string types in territory based collated databases.
> -------------------------------------------------------------------------------------------
>
>                 Key: DERBY-2721
>                 URL: https://issues.apache.org/jira/browse/DERBY-2721
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL, Store
>    Affects Versions: 10.3.1.4
>            Reporter: Mike Matrigali
>            Priority: Minor
>              Labels: derby_triage10_10
>
> Comparison of strings in a non unicode basic collation database is going to be slower
than comparing unicode values directly.  Indexes perform
> many such compares before finding a single key in a search.  
> Some suggestions for future work:
> o Somehow cache  CollationKey's for the strings and use them directly for compares rather
than the actual strings.
> o even better would be to use a functional index that actually stored CollationKey's
rather than the strings themselves, and then build the index on the
>    CollationKeys.  Depends on some sort of functional index work.  Something like  	
DERBY-455 would build the infrastructure to make this kind of
> index easy.

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