Uploaded image for project: 'Hive'
  1. Hive
  2. HIVE-3565

use hbase tables for writing intermediate directories across map-reduce boundaries

        Details

        • Type: New Feature
        • Status: Open
        • Priority: Major
        • Resolution: Unresolved
        • Affects Version/s: None
        • Fix Version/s: None
        • Component/s: HBase Handler, Query Processor
        • Labels:
          None

          Activity

          Hide
          Permalink
          namit Namit Jain added a comment -

          Consider a query like:

          select B.y, count(1) from
          A join B on A.x=B.x
          group by B.y;

          This will require 2 MR jobs. The first MR job will perform the join, and the second MR job will perform the group by (note that the 2nd MR job would have a
          identity mapper). If the first MR job could write the output of the join to a HBase table (which is keyed by B.y), the 2nd MR can be a map-only job which can
          simply scan the HBase table. This idea can be extended to joins as well.

          Show
          namit Namit Jain added a comment - Consider a query like: select B.y, count(1) from A join B on A.x=B.x group by B.y; This will require 2 MR jobs. The first MR job will perform the join, and the second MR job will perform the group by (note that the 2nd MR job would have a identity mapper). If the first MR job could write the output of the join to a HBase table (which is keyed by B.y), the 2nd MR can be a map-only job which can simply scan the HBase table. This idea can be extended to joins as well.

            People

            • Assignee:
              namit Namit Jain
              Reporter:
              namit Namit Jain
            • Votes:
              0 Vote for this issue
              Watchers:
              2 Start watching this issue

              Dates

              • Created:
                Updated:

                Development