greenplumn CXformJoinCommutativity 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/xforms/CXformJoinCommutativity.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CXformJoinCommutativity.h
/
/ @doc:
/ Transform join by commutativity
/---------------------------------------------------------------------------
#ifndef GPOPT_CXformJoinCommutativity_H
#define GPOPT_CXformJoinCommutativity_H
#include "gpos/base.h"
#include "gpopt/xforms/CXformExploration.h"
namespace gpopt
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CXformJoinCommutativity
/
/ @doc:
/ Commutative transformation of join
/
/---------------------------------------------------------------------------
class CXformJoinCommutativity : public CXformExploration
{
private:
public:
CXformJoinCommutativity(const CXformJoinCommutativity &) = delete;
/ ctor
explicit CXformJoinCommutativity(CMemoryPool *mp);
/ dtor
~CXformJoinCommutativity() override = default;
/ ident accessors
EXformId
Exfid() const override
{
return ExfJoinCommutativity;
}
/ return a string for xform name
const CHAR *
SzId() const override
{
return "CXformJoinCommutativity";
}
/ compatibility function
BOOL FCompatible(CXform::EXformId exfid) override;
/ compute xform promise for a given expression handle
EXformPromise
Exfp(CExpressionHandle & / exprhdl
) const override
{
return CXform::ExfpHigh;
}
/ actual transform
void Transform(CXformContext *pxfctxt, CXformResult *pxfres,
CExpression *pexpr) const override;
}; / class CXformJoinCommutativity
} / namespace gpopt
#endif / !GPOPT_CXformJoinCommutativity_H
/ EOF
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