//---------------------------------------------------------------------------
// @function:
// CDrvdPropScalar::Derive
//
// @doc:
// Derive scalar props
//
//---------------------------------------------------------------------------
void
CDrvdPropScalar::Derive
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl,
CDrvdPropCtxt * // pdpctxt
)
{
CScalar *popScalar = CScalar::PopConvert(exprhdl.Pop());
// call derivation functions on the operator
GPOS_ASSERT(NULL == m_pcrsDefined);
m_pcrsDefined = popScalar->PcrsDefined(pmp, exprhdl);
GPOS_ASSERT(NULL == m_pcrsSetReturningFunction);
m_pcrsSetReturningFunction = popScalar->PcrsSetReturningFunction(pmp, exprhdl);
GPOS_ASSERT(NULL == m_pcrsUsed);
m_pcrsUsed = popScalar->PcrsUsed(pmp, exprhdl);
// derive function properties
m_pfp = popScalar->PfpDerive(pmp, exprhdl);
// add defined and used columns of children
const ULONG ulArity = exprhdl.UlArity();
for (ULONG i = 0; i < ulArity; i++)
{
// only propagate properties from scalar children
if (exprhdl.FScalarChild(i))
{
m_pcrsDefined->Union(exprhdl.Pdpscalar(i)->PcrsDefined());
m_pcrsUsed->Union(exprhdl.Pdpscalar(i)->PcrsUsed());
m_pcrsSetReturningFunction->Union(exprhdl.Pdpscalar(i)->PcrsSetReturningFunction());
}
else
{
GPOS_ASSERT(CUtils::FSubquery(popScalar));
// parent operator is a subquery, add outer references
// from its relational child as used columns
m_pcrsUsed->Union(exprhdl.Pdprel(0)->PcrsOuter());
}
}
// derive existence of subqueries
GPOS_ASSERT(!m_fHasSubquery);
m_fHasSubquery = popScalar->FHasSubquery(exprhdl);
if (m_fHasSubquery)
{
m_ppartinfo = popScalar->PpartinfoDerive(pmp, exprhdl);
}
else
{
m_ppartinfo = GPOS_NEW(pmp) CPartInfo(pmp);
}
m_fHasNonScalarFunction = popScalar->FHasNonScalarFunction(exprhdl);
if (COperator::EopScalarProjectList == exprhdl.Pop()->Eopid())
{
m_ulDistinctAggs = CScalarProjectList::UlDistinctAggs(exprhdl);
m_fHasMultipleDistinctAggs = CScalarProjectList::FHasMultipleDistinctAggs(exprhdl);
}
if (COperator::EopScalarProjectElement == exprhdl.Pop()->Eopid())
{
if (m_fHasNonScalarFunction)
{
CScalarProjectElement *pspeProject = (CScalarProjectElement *)(exprhdl.Pop());
m_pcrsSetReturningFunction->Include(pspeProject->Pcr());
}
}
}
//---------------------------------------------------------------------------
// @function:
// CNormalizer::PexprPullUpProjectElements
//
// @doc:
// Pull up project elements from the given projection expression that do not
// exist in the given used columns set. The pulled up project elements must only
// use columns that are in the output columns of the parent operator. Returns
// a new expression that does not have the pulled up project elements. These
// project elements are appended to the given array.
//
//---------------------------------------------------------------------------
CExpression *
CNormalizer::PexprPullUpProjectElements
(
IMemoryPool *pmp,
CExpression *pexpr,
CColRefSet *pcrsUsed,
CColRefSet *pcrsOutput,
DrgPexpr **ppdrgpexprPrElPullUp // output: the pulled-up project elements
)
{
GPOS_ASSERT(NULL != pexpr);
GPOS_ASSERT(COperator::EopLogicalProject == pexpr->Pop()->Eopid());
GPOS_ASSERT(NULL != pcrsUsed);
GPOS_ASSERT(NULL != ppdrgpexprPrElPullUp);
GPOS_ASSERT(NULL != *ppdrgpexprPrElPullUp);
if (2 != pexpr->UlArity())
{
// the project's children were not extracted as part of the pattern in this xform
GPOS_ASSERT(0 == pexpr->UlArity());
pexpr->AddRef();
return pexpr;
}
DrgPexpr *pdrgpexprPrElNoPullUp = GPOS_NEW(pmp) DrgPexpr(pmp);
CExpression *pexprPrL = (*pexpr)[1];
const ULONG ulProjElements = pexprPrL->UlArity();
for (ULONG ul = 0; ul < ulProjElements; ul++)
{
CExpression *pexprPrEl = (*pexprPrL)[ul];
CScalarProjectElement *popPrEl = CScalarProjectElement::PopConvert(pexprPrEl->Pop());
CColRef *pcrDefined = popPrEl->Pcr();
CColRefSet *pcrsUsedByProjElem = CDrvdPropScalar::Pdpscalar(pexprPrEl->PdpDerive())->PcrsUsed();
// a proj elem can be pulled up only if the defined column is not in
// pcrsUsed and its used columns are in pcrOutput
pexprPrEl->AddRef();
if (!pcrsUsed->FMember(pcrDefined) && pcrsOutput->FSubset(pcrsUsedByProjElem))
{
(*ppdrgpexprPrElPullUp)->Append(pexprPrEl);
}
else
{
pdrgpexprPrElNoPullUp->Append(pexprPrEl);
}
}
CExpression *pexprNew = (*pexpr)[0];
pexprNew->AddRef();
if (0 == pdrgpexprPrElNoPullUp->UlLength())
{
pdrgpexprPrElNoPullUp->Release();
}
else
{
// some project elements could not be pulled up - need a project here
CExpression *pexprPrjList = GPOS_NEW(pmp) CExpression(pmp, GPOS_NEW(pmp) CScalarProjectList(pmp), pdrgpexprPrElNoPullUp);
pexprNew = GPOS_NEW(pmp) CExpression(pmp, GPOS_NEW(pmp) CLogicalProject(pmp), pexprNew, pexprPrjList);
}
return pexprNew;
}