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From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-5781) Investigate lifting the limit on the number of columns in a Derby table
Date Thu, 24 May 2012 16:28:29 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5781?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13282600#comment-13282600
] 

Mike Matrigali commented on DERBY-5781:
---------------------------------------

Note that current algorithms in the system may not scale well with arbitrary large number
of columns (may actually not work that well for 1012 columns also).  So work in this area
probably should be more than
just changing the constant, for successful applications to actually use tables with large
number of columns.

 For instance I know that for store to get to the 1012'th column it has to work its way directly
through all the columns before it.    It is likely a user looking for 
100,000 column table is really looking for a database implemented based on a column based
store rather than a row based one.  
                
> Investigate lifting the limit on the number of columns in a Derby table
> -----------------------------------------------------------------------
>
>                 Key: DERBY-5781
>                 URL: https://issues.apache.org/jira/browse/DERBY-5781
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>            Reporter: Rick Hillegas
>             Fix For: 10.10.0.0
>
>
> Derby tables are limited to 1012 columns. This arbitrary limit is not found in the SQL
Standard and is the value of Limits.DB2_MAX_ELEMENTS_IN_SELECT_LIST. We should investigate
lifting this limit based on user demand: http://old.nabble.com/limit-on-the-number-of-columns-to33901308.html#a33901308

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