// -----------------------------------------------------------------------
// MultJoin::recomputeOuterReferences()
// -----------------------------------------------------------------------
void MultiJoin::recomputeOuterReferences()
{
// ---------------------------------------------------------------------
// Delete all those input values that are no longer referenced on
// this operator.
// ---------------------------------------------------------------------
if (NOT getGroupAttr()->getCharacteristicInputs().isEmpty())
{
ValueIdSet outerRefs = getGroupAttr()->getCharacteristicInputs();
// Weed out those expressions not needed by my selectionPred and joinPred
// xxx instead of taking this from getLocalJoinPreds, should I take it
// from MultiJoin selectionPred??? refer to getLocalJoinPreds definition
// and consider preds that referencing inputs!!!
ValueIdSet exprSet = jbbSubset_.getLocalJoinPreds(); // from JbbSubsetAnalysis
// Need to include LocalDependentPreds later when supported. Ok now for inner MultiJoins
exprSet.weedOutUnreferenced(outerRefs);
// Add back those expressiones needed by my children
Int32 arity = getArity();
// outputs produced by JBBCs in this MultiJoin
ValueIdSet jbbcOutputs;
for (Int32 i = 0; i < arity; i++)
{
outerRefs += child(i)->getGroupAttr()->getCharacteristicInputs();
jbbcOutputs += child(i)->getGroupAttr()->getCharacteristicOutputs();
// these inputs are provided by jbbcs in this MultiJoin
}
// account for TSJs i.e. values flowing from
// one jbbc to another within this MultiJoin
outerRefs -= jbbcOutputs;
getGroupAttr()->setCharacteristicInputs(outerRefs);
}
return;
} // MultiJoin::recomputeOuterReferences()
