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A B commented on DERBY-2998: ---------------------------- Is there any kind of detailed write-up or functional spec for the approach that is being pursued in the patches thus far (esp. d2998-9.diff)? I took a look at: http://wiki.apache.org/db-derby/OLAPRowNumber but the "proposed changes" section on that page is rather abbreviated. In particular, a description of how the query tree will look at various points during compilation (esp. 1) when created, 2) after preprocessing, and 3) after "modification of access paths"--i.e. just before code generation) might be useful in trying to a) evaluate the approach, and b) offer feedback/suggestions on the various issues that are occurring. Also useful would be a simple example of the intended compilation- and execution-time processing that should occur when ROW_NUMBER() is in play. Apologies if the write-up already exists and I just missed it... One quick comment from scanning d2998-9.diff: Can you explain the purpose of the following change in SelectNode.java? /* Intentionally hide this.resultColumns */ ResultColumnList resultColumns = this.resultColumns.copyListAndObjects(); It appears to cause any RCL expression referenced by an outer query to fail with the same error as what Rick reported for ROW_ORDER(), ex: ij> select * from (select i+j as x from hmm) a(x) where x > 0; ERROR XJ001: Java exception: 'ASSERT FAILED sourceResultSetNumber expected to be >= 0 for null.X But that same statement succeeds if you remove the above lines. Of course, if you remove those lines then the simple ROW_ORDER() queries that work with d2998-9.diff applied stop working, so something is amiss somewhere. A writeup of what the intended behavior/query tree structure is meant to be here might help... > 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: d2998-4.diff, d2998-4.stat, d2998-5.diff, d2998-5.stat, > d2998-6.diff, d2998-6.stat, d2998-7.diff, d2998-7.stat, d2998-8.diff, > d2998-8.stat, d2998-9-derby.log, d2998-9.diff, d2998-9.stat, > d2998-doc-1.diff, d2998-doc-1.stat, d2998-test.diff, d2998-test.stat, > d2998-test2.diff, d2998-test2.stat, d2998-test3.diff, d2998-test3.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 -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.