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https://issues.apache.org/jira/browse/DERBY-2998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12539052
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Thomas Nielsen commented on DERBY-2998:
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Where would the best place be to insert/use/introduce the OLAPResultSet?
- in sqlgrammar.jj, when we add the RowNumberColumnNode we could also add an
"umbrella" OLAPResultSetNode to the resultset?
- in ProjectRestrictNode.modifyAccessPath(), once the optimizer selects the
best access path to the data?
- any other place I've missed?
Index based queries run the second option and will insert an IndexToBaseRowNode
in the querytree during optimization if an index is present and will be used
for accessing the rows. This ends up generating the IndexRowToBaseRowResultSet
bytecode.
Ordering queries use the first option (if I'm not mistaken), and insert a
OrderByNode during querytree generation, ending up in the proper flagging of
the existing resultset as ordered.
I know upfront that I will need a OLAPResultSet, so it might be appropriate to
just add one in sqlgrammar.jj? But then again it might be irrelvant so I should
add it at optimizing?
Any input appreciated!
> Add support for ROW_NUMBER() window function
> --------------------------------------------
>
> Key: DERBY-2998
> URL: https://issues.apache.org/jira/browse/DERBY-2998
> Project: Derby
> Issue Type: Sub-task
> Components: SQL
> Reporter: Thomas Nielsen
> Assignee: Thomas Nielsen
> Priority: Minor
> Attachments: row_number_prototype-2c.diff,
> row_number_prototype-2c.stat
>
>
> As part of implementing the overall OLAP Operations features of SQL
> (DERBY-581), implement the ROW_NUMBER() window function.
> More information about this feature is available at
> http://wiki.apache.org/db-derby/OLAPRowNumber
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