//---------------------------------------------------------------------------
// @function:
// CLogical::PcrsDeriveOuterIndexGet
//
// @doc:
// Derive outer references for index get and dynamic index get operators
//
//---------------------------------------------------------------------------
CColRefSet *
CLogical::PcrsDeriveOuterIndexGet
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl
)
{
ULONG ulArity = exprhdl.UlArity();
CColRefSet *pcrsOuter = GPOS_NEW(pmp) CColRefSet(pmp);
CColRefSet *pcrsOutput = PcrsDeriveOutput(pmp, exprhdl);
CColRefSet *pcrsUsed = GPOS_NEW(pmp) CColRefSet(pmp);
for (ULONG i = 0; i < ulArity; i++)
{
GPOS_ASSERT(exprhdl.FScalarChild(i));
CDrvdPropScalar *pdpscalar = exprhdl.Pdpscalar(i);
pcrsUsed->Union(pdpscalar->PcrsUsed());
}
// outer references are columns used by scalar children
// but are not included in the output columns of relational children
pcrsOuter->Union(pcrsUsed);
pcrsOuter->Exclude(pcrsOutput);
pcrsOutput->Release();
pcrsUsed->Release();
return pcrsOuter;
}
//---------------------------------------------------------------------------
// @function:
// CLogical::PcrsDeriveOuter
//
// @doc:
// Derive outer references
//
//---------------------------------------------------------------------------
CColRefSet *
CLogical::PcrsDeriveOuter
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl,
CColRefSet *pcrsUsedAdditional
)
{
ULONG ulArity = exprhdl.UlArity();
CColRefSet *pcrsOuter = GPOS_NEW(pmp) CColRefSet(pmp);
// collect output columns from relational children
// and used columns from scalar children
CColRefSet *pcrsOutput = GPOS_NEW(pmp) CColRefSet(pmp);
CColRefSet *pcrsUsed = GPOS_NEW(pmp) CColRefSet(pmp);
for (ULONG i = 0; i < ulArity; i++)
{
if (exprhdl.FScalarChild(i))
{
CDrvdPropScalar *pdpscalar = exprhdl.Pdpscalar(i);
pcrsUsed->Union(pdpscalar->PcrsUsed());
}
else
{
CDrvdPropRelational *pdprel = exprhdl.Pdprel(i);
pcrsOutput->Union(pdprel->PcrsOutput());
// add outer references from relational children
pcrsOuter->Union(pdprel->PcrsOuter());
}
}
if (NULL != pcrsUsedAdditional)
{
pcrsUsed->Include(pcrsUsedAdditional);
}
// outer references are columns used by scalar child
// but are not included in the output columns of relational children
pcrsOuter->Union(pcrsUsed);
pcrsOuter->Exclude(pcrsOutput);
pcrsOutput->Release();
pcrsUsed->Release();
return pcrsOuter;
}
//---------------------------------------------------------------------------
// @function:
// CConstExprEvaluatorDXL::FValidInput
//
// @doc:
// Checks if the given expression is a valid input for constant expression evaluation,
// i.e., a scalar expression without variables and without subqueries.
// If it returns false, it sets the contents of the error message appropriately.
// If szErrorMsg is not null and this function returns false, szErrorMsg will contain
// the error message.
//
//---------------------------------------------------------------------------
BOOL
CConstExprEvaluatorDXL::FValidInput
(
CExpression *pexpr,
const CHAR **szErrorMsg
)
{
GPOS_ASSERT(NULL != pexpr);
// if the expression is not scalar, we should not try to evaluate it
if (!pexpr->Pop()->FScalar())
{
if (NULL != szErrorMsg)
{
*szErrorMsg = pexpr->Pop()->SzId();
}
return false;
}
// if the expression has a subquery, we should not try to evaluate it
if (CDrvdPropScalar::Pdpscalar(pexpr->PdpDerive())->FHasSubquery())
{
if (NULL != szErrorMsg)
{
*szErrorMsg = "expression containing subqueries";
}
return false;
}
// if the expression uses or defines any variables, we should not try to evaluate it
CDrvdPropScalar *pdpScalar = CDrvdPropScalar::Pdpscalar(pexpr->PdpDerive());
if (0 != pdpScalar->PcrsUsed()->CElements() ||
0 != pdpScalar->PcrsDefined()->CElements())
{
if (NULL != szErrorMsg)
{
*szErrorMsg = "expression with variables";
}
return false;
}
return true;
}
//---------------------------------------------------------------------------
// @function:
// CColumnFactory::AddComputedToUsedColsMap
//
// @doc:
// Add the map between computed column and its used columns
//
//---------------------------------------------------------------------------
void
CColumnFactory::AddComputedToUsedColsMap
(
CExpression *pexpr
)
{
GPOS_ASSERT(NULL != pexpr);
GPOS_ASSERT(NULL != m_phmcrcrs);
const CScalarProjectElement *popScPrEl = CScalarProjectElement::PopConvert(pexpr->Pop());
CColRef *pcrComputedCol = popScPrEl->Pcr();
CDrvdPropScalar *pdpscalar = CDrvdPropScalar::GetDrvdScalarProps(pexpr->PdpDerive());
CColRefSet *pcrsUsed = pdpscalar->PcrsUsed();
if (NULL != pcrsUsed && 0 < pcrsUsed->Size())
{
#ifdef GPOS_DEBUG
BOOL fres =
#endif // GPOS_DEBUG
m_phmcrcrs->Insert(pcrComputedCol, GPOS_NEW(m_mp) CColRefSet(m_mp, *pcrsUsed));
GPOS_ASSERT(fres);
}
}
//---------------------------------------------------------------------------
// @function:
// CConstraint::PcnstrFromScalarExpr
//
// @doc:
// Create constraint from scalar expression and pass back any discovered
// equivalence classes
//
//---------------------------------------------------------------------------
CConstraint *
CConstraint::PcnstrFromScalarExpr
(
IMemoryPool *pmp,
CExpression *pexpr,
DrgPcrs **ppdrgpcrs // output equivalence classes
)
{
GPOS_ASSERT(NULL != pexpr);
GPOS_ASSERT(pexpr->Pop()->FScalar());
GPOS_ASSERT(NULL != ppdrgpcrs);
GPOS_ASSERT(NULL == *ppdrgpcrs);
(void) pexpr->PdpDerive();
CDrvdPropScalar *pdpScalar = CDrvdPropScalar::Pdpscalar(pexpr->Pdp(CDrvdProp::EptScalar));
CColRefSet *pcrs = pdpScalar->PcrsUsed();
ULONG ulCols = pcrs->CElements();
if (0 == ulCols)
{
// TODO: - May 29, 2012: in case of an expr with no columns (e.g. 1 < 2),
// possibly evaluate the expression, and return a "TRUE" or "FALSE" constraint
return NULL;
}
if (1 == ulCols)
{
CColRef *pcr = pcrs->PcrFirst();
if (!CUtils::FConstrainableType(pcr->Pmdtype()->Pmdid()))
{
return NULL;
}
CConstraint *pcnstr = NULL;
*ppdrgpcrs = GPOS_NEW(pmp) DrgPcrs(pmp);
// first, try creating a single interval constraint from the expression
pcnstr = CConstraintInterval::PciIntervalFromScalarExpr(pmp, pexpr, pcr);
if (NULL == pcnstr && CUtils::FScalarArrayCmp(pexpr))
{
// if the interval creation failed, try creating a disjunction or conjunction
// of several interval constraints in the array case
pcnstr = PcnstrFromScalarArrayCmp(pmp, pexpr, pcr);
}
if (NULL != pcnstr)
{
AddColumnToEquivClasses(pmp, pcr, ppdrgpcrs);
}
return pcnstr;
}
switch (pexpr->Pop()->Eopid())
{
case COperator::EopScalarBoolOp:
return PcnstrFromScalarBoolOp(pmp, pexpr, ppdrgpcrs);
case COperator::EopScalarCmp:
return PcnstrFromScalarCmp(pmp, pexpr, ppdrgpcrs);
default:
return NULL;
}
}
//---------------------------------------------------------------------------
// @function:
// CLogicalDynamicGetBase::PstatsDeriveFilter
//
// @doc:
// Derive stats from base table using filters on partition and/or index columns
//
//---------------------------------------------------------------------------
IStatistics *
CLogicalDynamicGetBase::PstatsDeriveFilter
(
IMemoryPool *pmp,
CExpressionHandle &exprhdl,
CExpression *pexprFilter
)
const
{
CExpression *pexprFilterNew = NULL;
CConstraint *pcnstr = m_ppartcnstr->PcnstrCombined();
if (m_fPartial && NULL != pcnstr && !pcnstr->FUnbounded())
{
if (NULL == pexprFilter)
{
pexprFilterNew = pcnstr->PexprScalar(pmp);
pexprFilterNew->AddRef();
}
else
{
pexprFilterNew = CPredicateUtils::PexprConjunction(pmp, pexprFilter, pcnstr->PexprScalar(pmp));
}
}
else if (NULL != pexprFilter)
{
pexprFilterNew = pexprFilter;
pexprFilterNew->AddRef();
}
CColRefSet *pcrsStat = GPOS_NEW(pmp) CColRefSet(pmp);
CDrvdPropScalar *pdpscalar = NULL;
if (NULL != pexprFilterNew)
{
pdpscalar = CDrvdPropScalar::Pdpscalar(pexprFilterNew->PdpDerive());
pcrsStat->Include(pdpscalar->PcrsUsed());
}
// requesting statistics on distribution columns to estimate data skew
if (NULL != m_pcrsDist)
{
pcrsStat->Include(m_pcrsDist);
}
IStatistics *pstatsFullTable = PstatsBaseTable(pmp, exprhdl, m_ptabdesc, pcrsStat);
pcrsStat->Release();
if (NULL == pexprFilterNew || pdpscalar->FHasSubquery())
{
return pstatsFullTable;
}
CStatsPred *pstatspred = CStatsPredUtils::PstatspredExtract
(
pmp,
pexprFilterNew,
NULL /*pcrsOuterRefs*/
);
pexprFilterNew->Release();
IStatistics *pstatsResult = pstatsFullTable->PstatsFilter
(
pmp,
pstatspred,
true /* fCapNdvs */
);
pstatspred->Release();
pstatsFullTable->Release();
return pstatsResult;
}