[jira] [Created] (TRAFODION-2777) Fix latent bug unmasked by JIRA TRAFODION-2765 fix

["David Wayne Birdsall (JIRA)" <ji...@apache.org>]

David Wayne Birdsall created TRAFODION-2777:
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             Summary: Fix latent bug unmasked by JIRA TRAFODION-2765 fix
                 Key: TRAFODION-2777
                 URL: https://issues.apache.org/jira/browse/TRAFODION-2777
             Project: Apache Trafodion
          Issue Type: Bug
          Components: sql-cmp
    Affects Versions: 2.3-incubating
         Environment: All
            Reporter: David Wayne Birdsall
            Assignee: David Wayne Birdsall


The fix to JIRA TRAFODION-2765 unmasked another bug that causes regression test compGeneral/TEST006 to fail sometimes. The nature of the bug is that a query plan on a table with no statistics sometimes flips over to an MDAM plan where it wasn't before. One example of this that I saw happened in a release build while in a debug build the test passed.

The following script (sometimes!) reproduces the bug:

?section setup

create table t006t9 (a int not null primary key, b int, c int) salt using 2 partitions ;
create index t006t9ix1 on t006t9(b) ;

insert into t006t9 values (1,2,3), (10,20,30);
prepare expl from
select operator, cardinality,
       cast(substring(description, position('scan_type: ' in description), position('object_type: ' in description) - position('scan_type: ' in description)) as char(100)) scan_type
from table(explain(null, 'S'))
where operator like '%SCAN%';

?section doit

prepare s from
select a,b from t006t9 <<+ index TRAFODION.SCH.T006T9IX1>> where b > 10;
execute expl;



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