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From Eric Owhadi <eric.owh...@esgyn.com>
Subject RE: SEABASE/TEST010 error?
Date Fri, 18 Mar 2016 16:43:49 GMT
Actually, I found the root cause.

I had modified a function that looked weird in a test branch:

NABoolean FileScanOptimizer::isMultipleProbes() const

{

  CostScalar repeatCount = getContext().getPlan()->getPhysicalProperty()->

    getDP2CostThatDependsOnSPP()->getRepeatCountForOperatorsInDP2() ;

  CollIndex numCols =
getContext().getInputLogProp()->getColStats().entries();



  return (repeatCount.isGreaterThanOne()) OR (numCols > 0);

}



And instead forced it to return true always, just for test. As I noticed
that this would always return false, while I would expect it to return true
if I understand what the name of the function means.



And I had forgotten that file change when working on this new PR. I guess
git checkout –b “newbranch”  is not behaving the way I would expect since
it did not restore the file from my test branch…



When restoring the original file, the test passed.



BUT I still don’t believe not using INDEX scan is correct. Index mdam scan
should be better.



So I suspect that what I discovered on this isMultipleProbes is really a
bug, even if I am far from understanding the whole MDAM compiler business.



Thought?

Eric



*From:* Eric Owhadi [mailto:eric.owhadi@esgyn.com]
*Sent:* Friday, March 18, 2016 10:41 AM
*To:* 'dev@trafodion.incubator.apache.org' <
dev@trafodion.incubator.apache.org>
*Subject:* SEABASE/TEST010 error?



Hi Trafodioneers,

Trying to pass regression tests for my next pull request, but stumbled on
failure on SEABASE/TEST010

Given that my changes have nothing to do around compiler, there is no way
it could have affected this.

Any clue?

To me, the index_scan is the correct plan, so look like the EXPECTED010  is
wrong?





DIFF010 is :

10502c10502

< . . 1 TRAFODION_SCAN T010T4 1.00E+009

---

> . . 1 TRAFODION_index_scan T010IX1 1.00E+009



Where this is the LOG associated:

>>showddl t010t4 ;



CREATE TABLE TRAFODION.SCH.T010T4

  (

    A                                INT NO DEFAULT NOT NULL NOT DROPPABLE

  , B                                INT DEFAULT NULL

  , C                                INT DEFAULT NULL

 , PRIMARY KEY (A ASC)

  )

  SALT USING 4 PARTITIONS

;



CREATE INDEX T010IX1 ON TRAFODION.SCH.T010T4

  (

    B ASC

  )

  HBASE_OPTIONS

  (

    DATA_BLOCK_ENCODING = 'FAST_DIFF',

    COMPRESSION = 'GZ'

  )

SALT LIKE TABLE

;



--- SQL operation complete.

>>insert into t010t4 values (1,1,1) ;



--- 1 row(s) inserted.

>>prepare s from select a from t010t4 <<+cardinality 10e8>> where b >
0 ;



--- SQL command prepared.

>>explain options 'f' s ;



LC   RC   OP   OPERATOR              OPT       DESCRIPTION           CARD

---- ---- ---- --------------------  --------  --------------------
---------



1    .    2    root
1.00E+009

.    .    1    trafodion_index_scan            T010IX1
1.00E+009



--- SQL operation complete.

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