Uploaded image for project: 'IMPALA'
  1. IMPALA
  2. IMPALA-10235

Averaged timer profile counters can be negative for trivial queries

    XMLWordPrintableJSON

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: Impala 4.0.0
    • Component/s: None
    • Labels:
    • Epic Color:
      ghx-label-10

      Description

      Steps to reproduce on master:

      stakiar @ stakiar-desktop -bash ~/Impala 2020-10-13 11:13:02 master
       [74] → ./bin/impala-shell.sh -q "select sleep(100) from functional.alltypes limit 25" -p > profile-output.txt
      ...
      Query: select sleep(100) from functional.alltypes limit 25
      Query submitted at: 2020-10-13 11:13:07 (Coordinator: http://stakiar-desktop:25000)
      Query progress can be monitored at: http://stakiar-desktop:25000/query_plan?query_id=694f94671571d4d1:cdec9db900000000
      Fetched 25 row(s) in 2.64s
      

      Attached the contents of profile-output.txt

      Relevant portion of the profile:

          Averaged Fragment F00:(Total: 2s603ms, non-child: 272.519us, % non-child: 0.01%)
      ...
             - CompletionTime: -1665218428.000ns
      ...
             - TotalThreadsTotalWallClockTime: -1686005515.000ns
               - TotalThreadsSysTime: 0.000ns
               - TotalThreadsUserTime: 2.151ms
      ...
             - TotalTime: -1691524485.000ns
      

      For whatever reason, this only affects the averaged fragment profile. For this query, there was only one coordinator fragment and thus only one fragment instance. The coordinator fragment instance showed normal timer values:

          Coordinator Fragment F00:
      ...
               - CompletionTime: 2s629ms
      ...
               - TotalThreadsTotalWallClockTime: 2s608ms
                 - TotalThreadsSysTime: 0.000ns
                 - TotalThreadsUserTime: 2.151ms
      ...
               - TotalTime: 2s603ms
      

        Attachments

        1. profile-output.txt
          18 kB
          Sahil Takiar

          Activity

            People

            • Assignee:
              tarmstrong Tim Armstrong
              Reporter:
              stakiar Sahil Takiar
            • Votes:
              0 Vote for this issue
              Watchers:
              2 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: