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Posted to issues@calcite.apache.org by "Julian Hyde (JIRA)" <ji...@apache.org> on 2014/09/06 01:08:32 UTC

[jira] [Created] (OPTIQ-404) MergeProjectRule should not construct RexPrograms for simple mappings

Julian Hyde created OPTIQ-404:
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             Summary: MergeProjectRule should not construct RexPrograms for simple mappings
                 Key: OPTIQ-404
                 URL: https://issues.apache.org/jira/browse/OPTIQ-404
             Project: Optiq
          Issue Type: Bug
            Reporter: Julian Hyde
            Assignee: Julian Hyde


MergeProjectRule should not construct RexPrograms when it is dealing with projections that are simple mappings or permutations. It can combine the mappings using less computation and memory.

Further, if either of the projects is the identity, MergeProjectRule should do nothing; it should let RemoveTrivialProjectRule deal with it.

This should reduce the amount of memory required for complex planning, in particular when there are large joins and many calls to SwapJoinRule.  OPTIQ-62 is a better but more complex solution to the same issue.



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