[jira] [Commented] (DERBY-3955) test lang/selectivity.sql can be revived

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

    [ https://issues.apache.org/jira/browse/DERBY-3955?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13877744#comment-13877744 ] 

Myrna van Lunteren commented on DERBY-3955:
-------------------------------------------

I have not committed the patch because I ran into trouble when I ran the lang._Suite.

The behavior is that the expected row count for some of the test cases is different when run in the suite, and also, it seemed that the expanded test caused failures in the test OptimizerOverridesTest, even though all three tests use CleanDatabaseSetup.

To overcome the failures in the OptimizerOverridesTest, I changed the name of the table used in SelectivityTest from 'test' (which was also used in OptimizerOverridesTest), to 'seltest', and that seemed to do the trick for that issue.

I debugged the other failures to where if the test GroupByExpressionTest is run before the expanded SelectivityTest, there is a failure after the following query:
------------
        s.executeUpdate("call SYSCS_UTIL.SYSCS_SET_RUNTIMESTATISTICS(1)");
        s.executeQuery("select template.id from " +
                "--DERBY-PROPERTIES joinOrder=fixed \n" + 
                "seltest, template --DERBY-PROPERTIES joinStrategy=hash, " +
                "index=null \n" +
                "where seltest.twenty = template.twenty " +
                "and seltest.two = template.two").close();
        checkEstimatedRowCount(conn,401000.625);
----------
and in 3 other places.

I *thought* the difference in estimated rowcount might be dependent on the name of the table also, because GroupByExpressionsTest also used table name 'test', but even after the change of the table name to 'seltest; in the SelectivityTest, this failure still occurred. I eliminated things from the GroupByExpressionsTest until I get this error when the only thing happening in the GroupByExpressionsTest is the creation of the 3 tables 'test', 'coal', and 'AllTypes'. If any of these 3 are eliminated, the error does not occur. 

Does anyone have a suggestion of how to prevent the earlier test from affecting the estimated rowcount in the later test?


> test lang/selectivity.sql can be revived
> ----------------------------------------
>
>                 Key: DERBY-3955
>                 URL: https://issues.apache.org/jira/browse/DERBY-3955
>             Project: Derby
>          Issue Type: Improvement
>          Components: Test
>            Reporter: Myrna van Lunteren
>            Priority: Minor
>         Attachments: DERBY-3955.diff1, DERBY-3955.diff2, derby-3955_sanityCheck_dont_commit_diff.txt, oldSelectivity.java
>
>
> One test that was contributed during the IBM contribution of derby code was not runnable at the time - lang/selectivity.sql.
> This test is still there, and I think might have some valuable regression tests if it gets adapted to the current functionality in Derby.
> Ideally too, it should get converted to junit, or at least be made to run through the langScripts junit suite.



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