Github user nonstop-qfchen commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/255#discussion_r49477153
--- Diff: core/sql/generator/GenPreCode.cpp ---
@@ -11412,9 +11924,54 @@ RelExpr * HbaseAccess::preCodeGen(Generator *
generator,
}
}
- // add all the key columns. If values are missing in hbase, then
atleast the key
+ // add key columns. If values are missing in hbase, then atleast the
key
// value is needed to retrieve a row.
-
HbaseAccess::addColReferenceFromVIDlist(getIndexDesc()->getIndexKey(),
retColRefSet_);
+ //only if needed. If there is already a non nullable non added non
nullable with default columns in the set, we should not need to add
+ //any other columns.
+ if (CmpCommon::getDefault(HBASE_FILTER_PREDS) == DF_MEDIUM &&
getMdamKeyPtr() == NULL){ //only enable column retrieval optimization with
DF_MEDIUM and not for MDAM scan
+ bool needAddingNonNullableColumn = true; //assume we need to add
one non nullable column
+ for (ValueId vid = retColRefSet_.init();// look for each
column in th eresult set if one match the criteria non null non added non
nullable with default
+ retColRefSet_.next(vid);
+ retColRefSet_.advance(vid))
+ {
+ if (originExePreds->isNotNullable(vid)){// it is non
nullable
+ NAColumn * nac;
+ switch (vid.getItemExpr()->getOperatorType()){
+ case ITM_BASECOLUMN:
+ nac =
((BaseColumn*)vid.getItemExpr())->getNAColumn();
+ break;
+ case ITM_INDEXCOLUMN:
+ nac =
((IndexColumn*)vid.getItemExpr())->getNAColumn();
+ break;
+ default:
+ break;
+ }
+ if (nac && !(nac->isAddedColumn() &&
nac->getDefaultValue())){//check if added and with default... notgood
+ needAddingNonNullableColumn = false; //
we found one column meeting all criteria
--- End diff --
Same comment before. this body of logic should be refactored into a method
on ValueId and we can that method here.
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