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From "Julian Hyde (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CALCITE-1635) Add MinRowCount metadata
Date Tue, 14 Feb 2017 22:17:41 GMT
Julian Hyde created CALCITE-1635:
------------------------------------

             Summary: Add MinRowCount metadata
                 Key: CALCITE-1635
                 URL: https://issues.apache.org/jira/browse/CALCITE-1635
             Project: Calcite
          Issue Type: Bug
            Reporter: Julian Hyde
            Assignee: Julian Hyde


Add {{MinRowCount}} metadata, that describes that a {{RelNode}} will never return fewer than
N rows.

The {{GROUP BY ()}} operation has a peculiar effect if its input is empty: it increases the
number of rows to 1. So, it is useful to know that a {{RelNode}} can never be empty, and a
{{MinRowCount}} of 1 or higher communicates that.



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