Uploaded image for project: 'Teiid'
  1. Teiid
  2. TEIID-1422

Limit pushing can result in inconsistent xml results

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Critical
    • Resolution: Done
    • Affects Version/s: 6.0.0
    • Fix Version/s: 7.1.1, 7.3
    • Component/s: Query Engine
    • Labels:
      None
    • Workaround:
      Workaround Exists
    • Workaround Description:
      Hide

      For non-rowlimit/rowlimitexception, which are only for xml document models, affected unordered limit application can instead use an order by to force the limit to be applied at its given position.

      Show
      For non-rowlimit/rowlimitexception, which are only for xml document models, affected unordered limit application can instead use an order by to force the limit to be applied at its given position.
    • Estimated Difficulty:
      Low

      Description

      A customer case (00393370) was using rowlimitexception and not actually triggering the exception when expected. This is due to our logic in rulepushlimit that allows an unordered limit to be pushed through union not all, select nodes, or dup removal. While the results may be consistent for some ordering of results there are many situations when you will get back far less results than the limit specifies. The intent was to more broadly push the limit rather than to apply it in a fully consistent manner. However this is problematic for situations, like the rowlimitexception logic that expect an exceptional condition to be triggered if the limit is exceeded.

      The best fix would be to just not push an unordered limit in these situations, then if the more aggressive pushing is desired by a user we can look at using a hint or some other mechanism to allow the pushing.

        Gliffy Diagrams

          Attachments

            Issue Links

              Activity

                People

                • Assignee:
                  shawkins Steven Hawkins
                  Reporter:
                  shawkins Steven Hawkins
                • Votes:
                  0 Vote for this issue
                  Watchers:
                  0 Start watching this issue

                  Dates

                  • Created:
                    Updated:
                    Resolved: