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From "Mike Matrigali (JIRA)" <derby-...@db.apache.org>
Subject [jira] Updated: (DERBY-884) allow and use backward scans on indexes.
Date Tue, 11 Apr 2006 23:19:22 GMT
     [ http://issues.apache.org/jira/browse/DERBY-884?page=all ]

Mike Matrigali updated DERBY-884:
---------------------------------

    Component: SQL
               Store

> allow and use backward scans on indexes.
> ----------------------------------------
>
>          Key: DERBY-884
>          URL: http://issues.apache.org/jira/browse/DERBY-884
>      Project: Derby
>         Type: Improvement

>   Components: SQL, Store
>     Versions: 10.1.2.2
>     Reporter: Mike Matrigali
>     Priority: Minor

>
> Improve the access interface to support backward scans, currently only forward scans
are supported.
> Improve the btree implementation to support backward scans.  The structure could support
this, the work just has not been done.  With
> row level locking, concurrent tree splitting, and current assumptions
> throughout the access method that scans go top/down, left to right the
> work to do a backward scan is harder than doing a forward scan.  Also
> once the store portion is done, there would be necessary changes to:
> optimizer, execution engine, and scan interface to allow the backward
> scan.  This would be a hard first project. 
> Improve the optimizer to understand derby indexes now support backward scans.
> Improve the execution engine to use the new backward scan interfaces to execute backward
scans.

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