greenplumn CLogicalSelect 代码
文件路径：/src/backend/gporca/libgpopt/src/operators/CLogicalSelect.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CLogicalSelect.cpp
/
/ @doc:
/ Implementation of select operator
/---------------------------------------------------------------------------
#include "gpopt/operators/CLogicalSelect.h"
#include "gpos/base.h"
#include "gpopt/base/CColRefSet.h"
#include "gpopt/base/CColRefSetIter.h"
#include "gpopt/base/CColRefTable.h"
#include "gpopt/base/COptCtxt.h"
#include "gpopt/operators/CExpression.h"
#include "gpopt/operators/CExpressionHandle.h"
#include "gpopt/operators/CPatternTree.h"
#include "gpopt/operators/CPredicateUtils.h"
#include "naucrates/statistics/CFilterStatsProcessor.h"
#include "naucrates/statistics/CStatisticsUtils.h"
using namespace gpopt;
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::CLogicalSelect
/
/ @doc:
/ Ctor
/
/---------------------------------------------------------------------------
CLogicalSelect::CLogicalSelect(CMemoryPool *mp)
: CLogicalUnary(mp), m_ptabdesc(nullptr)
{
m_phmPexprPartPred = GPOS_NEW(mp) ExprPredToExprPredPartMap(mp);
}
CLogicalSelect::CLogicalSelect(CMemoryPool *mp, CTableDescriptor *ptabdesc)
: CLogicalUnary(mp), m_ptabdesc(ptabdesc)
{
m_phmPexprPartPred = GPOS_NEW(mp) ExprPredToExprPredPartMap(mp);
}
CLogicalSelect::~CLogicalSelect()
{
m_phmPexprPartPred->Release();
}
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::DeriveOutputColumns
/
/ @doc:
/ Derive output columns
/
/---------------------------------------------------------------------------
CColRefSet *
CLogicalSelect::DeriveOutputColumns(CMemoryPool *, / mp
CExpressionHandle &exprhdl)
{
return PcrsDeriveOutputPassThru(exprhdl);
}
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::PkcDeriveKeys
/
/ @doc:
/ Derive key collection
/
/---------------------------------------------------------------------------
CKeyCollection *
CLogicalSelect::DeriveKeyCollection(CMemoryPool *, / mp
CExpressionHandle &exprhdl) const
{
return PkcDeriveKeysPassThru(exprhdl, 0 /* ulChild */);
}
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::PxfsCandidates
/
/ @doc:
/ Get candidate xforms
/
/---------------------------------------------------------------------------
CXformSet *
CLogicalSelect::PxfsCandidates(CMemoryPool *mp) const
{
CXformSet *xform_set = GPOS_NEW(mp) CXformSet(mp);
(void) xform_set->ExchangeSet(CXform::ExfSelect2Apply);
(void) xform_set->ExchangeSet(CXform::ExfRemoveSubqDistinct);
(void) xform_set->ExchangeSet(CXform::ExfInlineCTEConsumerUnderSelect);
(void) xform_set->ExchangeSet(CXform::ExfPushGbWithHavingBelowJoin);
(void) xform_set->ExchangeSet(CXform::ExfSelect2IndexGet);
(void) xform_set->ExchangeSet(CXform::ExfSelect2DynamicIndexGet);
(void) xform_set->ExchangeSet(CXform::ExfSelect2BitmapBoolOp);
(void) xform_set->ExchangeSet(CXform::ExfSelect2DynamicBitmapBoolOp);
(void) xform_set->ExchangeSet(CXform::ExfSimplifySelectWithSubquery);
(void) xform_set->ExchangeSet(CXform::ExfSelect2Filter);
return xform_set;
}
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::DeriveMaxCard
/
/ @doc:
/ Derive max card
/
/---------------------------------------------------------------------------
CMaxCard
CLogicalSelect::DeriveMaxCard(CMemoryPool *, / mp
CExpressionHandle &exprhdl) const
{
/ in case of a false condition or a contradiction, maxcard should be zero
CExpression *pexprScalar = exprhdl.PexprScalarRepChild(1);
if ((nullptr != pexprScalar &&
(CUtils::FScalarConstFalse(pexprScalar) ||
CUtils::FScalarConstBoolNull(pexprScalar))) ||
exprhdl.DerivePropertyConstraint()->FContradiction())
{
return CMaxCard(0 /*ull*/);
}
/ pass on max card of first child
return exprhdl.DeriveMaxCard(0);
}
/---------------------------------------------------------------------------
/ @function:
/ CLogicalSelect::PstatsDerive
/
/ @doc:
/ Derive statistics based on filter predicates
/
/---------------------------------------------------------------------------
IStatistics *
CLogicalSelect::PstatsDerive(CMemoryPool *mp, CExpressionHandle &exprhdl,
IStatisticsArray *stats_ctxt) const
{
GPOS_ASSERT(Esp(exprhdl) > EspNone);
IStatistics *child_stats = exprhdl.Pstats(0);
if (exprhdl.DeriveHasSubquery(1))
{
/ in case of subquery in select predicate, we return child stats
child_stats->AddRef();
return child_stats;
}
/ remove implied predicates from selection condition to avoid cardinality under-estimation
CExpression *pexprScalar = exprhdl.PexprScalarRepChild(1 /*child_index*/);
CExpression *pexprPredicate =
CPredicateUtils::PexprRemoveImpliedConjuncts(mp, pexprScalar, exprhdl);
/ split selection predicate into local predicate and predicate involving outer references
CExpression *local_expr = nullptr;
CExpression *expr_with_outer_refs = nullptr;
/ get outer references from expression handle
CColRefSet *outer_refs = exprhdl.DeriveOuterReferences();
CPredicateUtils::SeparateOuterRefs(mp, pexprPredicate, outer_refs,
&local_expr, &expr_with_outer_refs);
pexprPredicate->Release();
IStatistics *stats = CFilterStatsProcessor::MakeStatsFilterForScalarExpr(
mp, exprhdl, child_stats, local_expr, expr_with_outer_refs, stats_ctxt);
local_expr->Release();
expr_with_outer_refs->Release();
return stats;
}
/ compute partition predicate to pass down to n-th child.
/ given an input scalar expression, find out the predicate
/ in the scalar expression which is used for partitioning
/
/ clang-format off
/ Input Expr:
/ +--CScalarBoolOp (EboolopAnd)
/ |--CScalarArrayCmp Any (=)
/ | |--CScalarIdent "risk_set_row_id" (2)
/ | +--CScalarArray: {eleMDId: (23,1.0), arrayMDId: (1007,1.0) CScalarConst (32) CScalarConst (33) CScalarConst (43) CScalarConst (9) CScalarConst (10) CScalarConst (15) CScalarConst (16) CScalarConst (36) CScalarConst (11) CScalarConst (50) CScalarConst (46) CScalarConst (356) CScalarConst (468) CScalarConst (42)}
/ +--CScalarCmp (=)
/ |--CScalarIdent "value_date" (0)
/ +--CScalarConst (559094400000000.000)
/
/ Let's say the partition key is on value_date, then the extracted
/ predicate is as below:
/ Output Expr:
/ +--CScalarCmp (=)
/ |--CScalarIdent "value_date" (0)
/ +--CScalarConst (559094400000000.000)
/ clang-format on
CExpression *
CLogicalSelect::PexprPartPred(CMemoryPool *mp, CExpressionHandle &exprhdl,
CExpression *, /pexprInput
ULONG
#ifdef GPOS_DEBUG
child_index
#endif /GPOS_DEBUG
) const
{
GPOS_ASSERT(0 == child_index);
CExpression *pexprScalar = exprhdl.PexprScalarExactChild(1 /*child_index*/);
if (nullptr == pexprScalar)
{
/ no exact predicate is available (e.g. when we have a subquery in the predicate)
return nullptr;
}
/ get partition keys
CPartInfo *ppartinfo = exprhdl.DerivePartitionInfo();
GPOS_ASSERT(nullptr != ppartinfo);
/ we assume that the select is right on top of the dynamic get, so there
/ should be only one part consumer. If there is more, then we are higher up so
/ we do not push down any predicates
if (1 != ppartinfo->UlConsumers())
{
return nullptr;
}
/ check if a corresponding predicate has already been cached
CExpression *pexprPredOnPartKey = m_phmPexprPartPred->Find(pexprScalar);
if (pexprPredOnPartKey != nullptr)
{
/ predicate on partition key found in cache
pexprPredOnPartKey->AddRef();
return pexprPredOnPartKey;
}
CPartKeysArray *pdrgppartkeys = ppartinfo->Pdrgppartkeys(0 /*ulPos*/);
const ULONG ulKeySets = pdrgppartkeys->Size();
for (ULONG ul = 0; nullptr == pexprPredOnPartKey && ul < ulKeySets; ul++)
{
pexprPredOnPartKey = CPredicateUtils::PexprExtractPredicatesOnPartKeys(
mp, pexprScalar, (*pdrgppartkeys)[ul]->Pdrgpdrgpcr(),
nullptr, /pcrsAllowedRefs
true /fUseConstraints
);
}
if (pexprPredOnPartKey != nullptr)
{
/ insert the scalar expression and the corresponding partitioning predicate
/ in the hashmap
pexprPredOnPartKey->AddRef();
pexprScalar->AddRef();
m_phmPexprPartPred->Insert(pexprScalar, pexprPredOnPartKey);
}
return pexprPredOnPartKey;
}
/ EOF
相关信息
相关文章
greenplumn CExpressionFactorizer 源码
greenplumn CExpressionHandle 源码
greenplumn CExpressionPreprocessor 源码
greenplumn CExpressionUtils 源码