//---------------------------------------------------------------------------
// @function:
// CLogicalSetOp::PdrgpcrsInputMapped
//
// @doc:
// Get equivalence classes from one input child, mapped to output columns
//
//---------------------------------------------------------------------------
DrgPcrs *
CLogicalSetOp::PdrgpcrsInputMapped
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl,
ULONG ulChild
)
const
{
DrgPcrs *pdrgpcrsInput = exprhdl.Pdprel(ulChild)->Ppc()->PdrgpcrsEquivClasses();
const ULONG ulLen = pdrgpcrsInput->UlLength();
CColRefSet* pcrsChildInput = (*m_pdrgpcrsInput)[ulChild];
DrgPcrs *pdrgpcrs = GPOS_NEW(pmp) DrgPcrs(pmp);
for (ULONG ul = 0; ul < ulLen; ul++)
{
CColRefSet *pcrs = GPOS_NEW(pmp) CColRefSet(pmp);
pcrs->Include((*pdrgpcrsInput)[ul]);
pcrs->Intersection(pcrsChildInput);
if (0 == pcrs->CElements())
{
pcrs->Release();
continue;
}
// replace each input column with its corresponding output column
pcrs->Replace((*m_pdrgpdrgpcrInput)[ulChild], m_pdrgpcrOutput);
pdrgpcrs->Append(pcrs);
}
return pdrgpcrs;
}
//---------------------------------------------------------------------------
// @function:
// CLogical::PpcDeriveConstraintRestrict
//
// @doc:
// Derive constraint property only on the given columns
//
//---------------------------------------------------------------------------
CPropConstraint *
CLogical::PpcDeriveConstraintRestrict
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl,
CColRefSet *pcrsOutput
)
{
// constraint property from relational child
CPropConstraint *ppc = exprhdl.Pdprel(0)->Ppc();
DrgPcrs *pdrgpcrs = ppc->PdrgpcrsEquivClasses();
// construct new array of equivalence classes
DrgPcrs *pdrgpcrsNew = GPOS_NEW(pmp) DrgPcrs(pmp);
const ULONG ulLen = pdrgpcrs->UlLength();
for (ULONG ul = 0; ul < ulLen; ul++)
{
CColRefSet *pcrsEquiv = GPOS_NEW(pmp) CColRefSet(pmp);
pcrsEquiv->Include((*pdrgpcrs)[ul]);
pcrsEquiv->Intersection(pcrsOutput);
if (0 < pcrsEquiv->CElements())
{
pdrgpcrsNew->Append(pcrsEquiv);
}
else
{
pcrsEquiv->Release();
}
}
CConstraint *pcnstrChild = ppc->Pcnstr();
if (NULL == pcnstrChild)
{
return GPOS_NEW(pmp) CPropConstraint(pmp, pdrgpcrsNew, NULL);
}
DrgPcnstr *pdrgpcnstr = GPOS_NEW(pmp) DrgPcnstr(pmp);
// include only constraints on given columns
CColRefSetIter crsi(*pcrsOutput);
while (crsi.FAdvance())
{
CColRef *pcr = crsi.Pcr();
CConstraint *pcnstrCol = pcnstrChild->Pcnstr(pmp, pcr);
if (NULL == pcnstrCol)
{
continue;
}
if (pcnstrCol->FUnbounded())
{
pcnstrCol->Release();
continue;
}
pdrgpcnstr->Append(pcnstrCol);
}
CConstraint *pcnstr = CConstraint::PcnstrConjunction(pmp, pdrgpcnstr);
return GPOS_NEW(pmp) CPropConstraint(pmp, pdrgpcrsNew, pcnstr);
}
