Uploaded image for project: 'Hive'
  1. Hive
  2. HIVE-14018

Make IN clause row selectivity estimation customizable

    XMLWordPrintableJSON

    Details

      Description

      After HIVE-13287 went in, we calculate IN clause estimates natively (instead of just dividing incoming number of rows by 2). However, as the distribution of values of the columns is considered uniform, we might end up heavily underestimating/overestimating the resulting number of rows.

      This issue is to add a factor that multiplies the IN clause estimation so we can alleviate this problem. The solution is not very elegant, but it is the best we can do until we have histograms to improve our estimate.

        Attachments

        1. HIVE-14018.patch
          2 kB
          Jesus Camacho Rodriguez
        2. HIVE-14018.1.patch
          2 kB
          Jesus Camacho Rodriguez

          Issue Links

            Activity

              People

              • Assignee:
                jcamachorodriguez Jesus Camacho Rodriguez
                Reporter:
                jcamachorodriguez Jesus Camacho Rodriguez
              • Votes:
                0 Vote for this issue
                Watchers:
                2 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: