greenplumn CXformInnerApplyWithOuterKey2InnerJoin 代码
文件路径：/src/backend/gporca/libgpopt/src/xforms/CXformInnerApplyWithOuterKey2InnerJoin.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CXformInnerApplyWithOuterKey2InnerJoin.cpp
/
/ @doc:
/ Implementation of transform
/---------------------------------------------------------------------------
#include "gpopt/xforms/CXformInnerApplyWithOuterKey2InnerJoin.h"
#include "gpos/base.h"
#include "gpopt/base/CKeyCollection.h"
#include "gpopt/operators/CLogicalGbAgg.h"
#include "gpopt/operators/CLogicalInnerApply.h"
#include "gpopt/operators/CLogicalInnerJoin.h"
#include "gpopt/operators/CPatternLeaf.h"
#include "gpopt/operators/CPredicateUtils.h"
using namespace gpopt;
/---------------------------------------------------------------------------
/ @function:
/ CXformInnerApplyWithOuterKey2InnerJoin::CXformInnerApplyWithOuterKey2InnerJoin
/
/ @doc:
/ Ctor
/
/---------------------------------------------------------------------------
CXformInnerApplyWithOuterKey2InnerJoin::CXformInnerApplyWithOuterKey2InnerJoin(
CMemoryPool *mp)
: CXformExploration(
/ pattern
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalInnerApply(mp),
GPOS_NEW(mp)
CExpression(mp, GPOS_NEW(mp) CPatternLeaf(mp)), / left child
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalGbAgg(mp),
GPOS_NEW(mp) CExpression(
mp,
GPOS_NEW(mp) CPatternTree(mp)), / relational child of Gb
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp)
CPatternLeaf(mp)) / scalar project list of Gb
), / right child
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CPatternLeaf(mp)) / Apply predicate
))
{
}
/---------------------------------------------------------------------------
/ @function:
/ CXformInnerApplyWithOuterKey2InnerJoin::Exfp
/
/ @doc:
/ Compute xform promise for a given expression handle;
/
/---------------------------------------------------------------------------
CXform::EXformPromise
CXformInnerApplyWithOuterKey2InnerJoin::Exfp(CExpressionHandle &exprhdl) const
{
/ check if outer child has key and inner child has outer references
if (nullptr == exprhdl.DeriveKeyCollection(0) ||
0 == exprhdl.DeriveOuterReferences(1)->Size())
{
return ExfpNone;
}
return ExfpHigh;
}
/---------------------------------------------------------------------------
/ @function:
/ CXformInnerApplyWithOuterKey2InnerJoin::Transform
/
/ @doc:
/ Actual transformation
/
/---------------------------------------------------------------------------
void
CXformInnerApplyWithOuterKey2InnerJoin::Transform(CXformContext *pxfctxt,
CXformResult *pxfres,
CExpression *pexpr) const
{
GPOS_ASSERT(nullptr != pxfctxt);
GPOS_ASSERT(FPromising(pxfctxt->Pmp(), this, pexpr));
GPOS_ASSERT(FCheckPattern(pexpr));
CMemoryPool *mp = pxfctxt->Pmp();
/ extract components
CExpression *pexprOuter = (*pexpr)[0];
CExpression *pexprGb = (*pexpr)[1];
CExpression *pexprScalar = (*pexpr)[2];
if (0 < CLogicalGbAgg::PopConvert(pexprGb->Pop())->Pdrgpcr()->Size())
{
/ xform is not applicable if inner Gb has grouping columns
return;
}
if (CUtils::FHasSubqueryOrApply((*pexprGb)[0]))
{
/ Subquery/Apply must be unnested before reaching here
return;
}
/ decorrelate Gb's relational child
(*pexprGb)[0]->ResetDerivedProperties();
CExpression *pexprInner = nullptr;
CExpressionArray *pdrgpexpr = GPOS_NEW(mp) CExpressionArray(mp);
if (!CDecorrelator::FProcess(mp, (*pexprGb)[0], false /*fEqualityOnly*/,
&pexprInner, pdrgpexpr,
pexprOuter->DeriveOutputColumns()))
{
pdrgpexpr->Release();
return;
}
GPOS_ASSERT(nullptr != pexprInner);
CExpression *pexprPredicate =
CPredicateUtils::PexprConjunction(mp, pdrgpexpr);
/ join outer child with Gb's decorrelated child
pexprOuter->AddRef();
CExpression *pexprInnerJoin =
GPOS_NEW(mp) CExpression(mp, GPOS_NEW(mp) CLogicalInnerJoin(mp),
pexprOuter, pexprInner, pexprPredicate);
/ create grouping columns from the output of outer child
CColRefArray *pdrgpcrKey = nullptr;
CColRefArray *colref_array =
CUtils::PdrgpcrGroupingKey(mp, pexprOuter, &pdrgpcrKey);
pdrgpcrKey->Release(); / key is not used here
CLogicalGbAgg *popGbAgg = GPOS_NEW(mp) CLogicalGbAgg(
mp, colref_array, COperator::EgbaggtypeGlobal /*egbaggtype*/);
CExpression *pexprPrjList = (*pexprGb)[1];
pexprPrjList->AddRef();
CExpression *pexprNewGb =
GPOS_NEW(mp) CExpression(mp, popGbAgg, pexprInnerJoin, pexprPrjList);
/ add Apply predicate in a top Select node
pexprScalar->AddRef();
CExpression *pexprSelect =
CUtils::PexprLogicalSelect(mp, pexprNewGb, pexprScalar);
pxfres->Add(pexprSelect);
}
/ EOF
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