Row count derived from HFiles not used in cardinality estimation

[Barry Fritchman]

When NATable::originalCardinality_ is set from the result of estimateRowCount(), in the absence of statistics the optimizer's cardinality estimation code uses the default row count instead of the value assigned to the member variable.

[Trafodion-Gerrit (neo-devtools)]

Fix proposed to branch: master
Review: https://review.trafodion.org/708

[Trafodion-Gerrit (neo-devtools)]

Reviewed: https://review.trafodion.org/708
Committed: https://github.com/trafodion/core/commit/b062607e17cf478fd48922d4dc1f1bb76a830126
Submitter: Trafodion Jenkins
Branch: master

commit b062607e17cf478fd48922d4dc1f1bb76a830126
Author: Barry Fritchman <email address hidden>
Date: Tue Nov 11 18:07:12 2014 +0000

    Use HBase estimated row count if no stats exist

    In the absence of statistics, the row count for an HBase table
    is estimated using information in its HFiles. Previouly, this
    estimate was calculated and assigned to the NATable's
    originalCardinality_ member variable, but this did not result
    in it being used by the optimizer (the correct row count did
    not appear in the results of an Explain). The code to calculate
    the estimate is now invoked from HSHbaseTableDef::getRowCount(),
    which has the effect of it being used as intended.

    Change-Id: I3794e8368082b6f17e47fe686ec9a004aed27976
    Closes-Bug: #1388918