greenplumn CXformInnerApply2InnerJoinNoCorrelations 代码
文件路径：/src/backend/gporca/libgpopt/src/xforms/CXformInnerApply2InnerJoinNoCorrelations.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CXformInnerApply2InnerJoinNoCorrelations.cpp
/
/ @doc:
/ Implementation of transform
/---------------------------------------------------------------------------
#include "gpopt/xforms/CXformInnerApply2InnerJoinNoCorrelations.h"
#include "gpos/base.h"
using namespace gpopt;
/---------------------------------------------------------------------------
/ @function:
/ CXformInnerApply2InnerJoinNoCorrelations::Exfp
/
/ @doc:
/ Compute xform promise for a given expression handle;
/ outer references are not allowed
/
/---------------------------------------------------------------------------
CXform::EXformPromise
CXformInnerApply2InnerJoinNoCorrelations::Exfp(CExpressionHandle &exprhdl) const
{
/ if there are no outer references, or if all outer refs do not reference outer
/ child, the transformation is applicable
if (!exprhdl.HasOuterRefs(1 /*child_index*/) ||
CUtils::FInnerUsesExternalColsOnly(exprhdl))
{
return CXform::ExfpHigh;
}
return CXform::ExfpNone;
}
/---------------------------------------------------------------------------
/ @function:
/ CXformInnerApply2InnerJoinNoCorrelations::Transform
/
/ @doc:
/ Actual transformation
/
/---------------------------------------------------------------------------
void
CXformInnerApply2InnerJoinNoCorrelations::Transform(CXformContext *pxfctxt,
CXformResult *pxfres,
CExpression *pexpr) const
{
GPOS_ASSERT(nullptr != pxfctxt);
GPOS_ASSERT(FPromising(pxfctxt->Pmp(), this, pexpr));
GPOS_ASSERT(FCheckPattern(pexpr));
CreateJoinAlternative(pxfctxt, pxfres, pexpr);
}
/ EOF
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