[jira] Updated: (DERBY-4046) PredicatePushdownTest does not properly test for predicate pushdown in all cases

["Myrna van Lunteren (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DERBY-4046?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Myrna van Lunteren updated DERBY-4046:
--------------------------------------

    Urgency: Normal
     Labels: derby_triage10_8  (was: )

> PredicatePushdownTest does not properly  test for predicate pushdown  in all cases
> ----------------------------------------------------------------------------------
>
>                 Key: DERBY-4046
>                 URL: https://issues.apache.org/jira/browse/DERBY-4046
>             Project: Derby
>          Issue Type: Bug
>          Components: Test
>    Affects Versions: 10.5.1.1
>            Reporter: Kathey Marsden
>              Labels: derby_triage10_8
>
> In DERBY-3819 Knut commented that the JUnit test PredicatePushdownTest is no longer properly testing predicate pushdown after conversion.
> https://issues.apache.org/jira/browse/DERBY-3819?focusedCommentId=12669371#action_12669371
> There is a comment in the test:
>      // [We]can tell if a predicate has been "pushed" by looking at
>         // the query plan information for the tables in question:
>         // if the table has an index on a column that is used as
>         // part of the pushed predicate, then the optimizer will
>         // (for these tests) do an Index scan instead of a Table
>         // scan. If the table does not have such an index then the
>         // predicate will show up as a "qualifier" for a Table
>         // scan. In all of these tests T3 and T4 have appropriate
>         // indexes, so if we push a predicate to either of those
>         // tables we should see index scans. Neither T1 nor T2 has
>         // indexes, so if we push a predicate to either of those
>         // tables we should see a qualifier in the table scan
>         // information.
> So I think that means in the case of index scans our checks are ok, but for table scans we should also be checking the qualifiers.  The join strategy checks  are not really relevant except that hash join prevents predicate pushdown.

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