[jira] Created: (DERBY-619) Make scan Qualifiers smart enough to handle comparisons between columns in the same row

["Rick Hillegas (JIRA)" <de...@db.apache.org>]

Make scan Qualifiers smart enough to handle comparisons between columns in the same row
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         Key: DERBY-619
         URL: http://issues.apache.org/jira/browse/DERBY-619
     Project: Derby
        Type: Improvement
    Reporter: Rick Hillegas


Right now we can push the following restriction fragment into the Store: "col < CONSTANT". It would be good if we could also push "col1 < col2" into the Store. Same goes for =, !=, >, etc..

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[jira] Updated: (DERBY-619) Make scan Qualifiers smart enough to handle comparisons between columns in the same row

["Mike Matrigali (JIRA)" <de...@db.apache.org>]

     [ http://issues.apache.org/jira/browse/DERBY-619?page=all ]

Mike Matrigali updated DERBY-619:
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    Component: SQL
               Store

Implementation would require changes both to the store Qualifier interface and to the language level to generate the new Qualifiers.  We could push all qualifier processing into store, but I am not sure that is the best model.  Currently the qualifier processing is done in store at a very low level while holding a latch on the page.  The restriction of a single column allows the optimization of processing the columns in order on the page and one can stop getting columns if a qualifier fails.  Once multiple columns are required it gets much more complicated, and it probably best to just select all the columns into the row buffer and then run the qualifiers.  Once the row has been read into memory there is not much overhead in language running the qualiffier vs. store, especially if group fetch is being used.

Before we add multiple column qualifiers, I would rather see other qualifier improvements like IN list processing.

> Make scan Qualifiers smart enough to handle comparisons between columns in the same row
> ---------------------------------------------------------------------------------------
>
>          Key: DERBY-619
>          URL: http://issues.apache.org/jira/browse/DERBY-619
>      Project: Derby
>         Type: Improvement
>   Components: SQL, Store
>     Reporter: Rick Hillegas

>
> Right now we can push the following restriction fragment into the Store: "col < CONSTANT". It would be good if we could also push "col1 < col2" into the Store. Same goes for =, !=, >, etc..

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