Details

    • Type: Improvement Improvement
    • Status: Patch Available
    • Priority: Minor Minor
    • Resolution: Unresolved
    • Affects Version/s: 0.10.0
    • Fix Version/s: None
    • Component/s: Query Processor, SQL
    • Labels:
      None

      Description

      Currently, hive supports only equi-join which means all joining columns should be related only with equal operator(= or <=>).
      It seemed to be not easy to provide non-equi join in general manner but if one of table is small enough to be fit in memory, it might be possible to be implemented rather easily by exploiting current implementation of MapJoin.

        Activity

        Navis made changes -
        Status Open [ 1 ] Patch Available [ 10002 ]
        Navis made changes -
        Summary Implement map-side non-equi join Implement non-equi mapjoin
        Assignee Navis [ navis ]
        Affects Version/s 0.10.0 [ 12320745 ]
        Description It's rather simple to implement non-equi join in mapjoin by replacing hashmap to treemap, if it's targeted for single column. And if it's targeted two or more columns we can facilitate lucene file for lookup in mapjoin operator.

        I wish I could provide the patch but it's not my decision by contract. I believe someone can implement this for public use.
        Currently, hive supports only equi-join which means all joining columns should be related only with equal operator(= or <=>).
        It seemed to be not easy to provide non-equi join in general manner but if one of table is small enough to be fit in memory, it might be possible to be implemented rather easily by exploiting current implementation of MapJoin.
        Carl Steinbach made changes -
        Component/s SQL [ 12315100 ]
        Carl Steinbach made changes -
        Field Original Value New Value
        Component/s Query Processor [ 12312586 ]
        Navis created issue -

          People

          • Assignee:
            Navis
            Reporter:
            Navis
          • Votes:
            4 Vote for this issue
            Watchers:
            12 Start watching this issue

            Dates

            • Created:
              Updated:

              Development