greenplumn CXformExpandNAryJoinDP 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/xforms/CXformExpandNAryJoinDP.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2013 EMC Corp.
/
/ @filename:
/ CXformExpandNAryJoinDP.h
/
/ @doc:
/ Expand n-ary join into series of binary joins using dynamic
/ programming
/---------------------------------------------------------------------------
#ifndef GPOPT_CXformExpandNAryJoinDP_H
#define GPOPT_CXformExpandNAryJoinDP_H
#include "gpos/base.h"
#include "gpopt/xforms/CXformExploration.h"
namespace gpopt
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CXformExpandNAryJoinDP
/
/ @doc:
/ Expand n-ary join into series of binary joins using dynamic
/ programming
/
/---------------------------------------------------------------------------
class CXformExpandNAryJoinDP : public CXformExploration
{
private:
public:
CXformExpandNAryJoinDP(const CXformExpandNAryJoinDP &) = delete;
/ ctor
explicit CXformExpandNAryJoinDP(CMemoryPool *mp);
/ dtor
~CXformExpandNAryJoinDP() override = default;
/ ident accessors
EXformId
Exfid() const override
{
return ExfExpandNAryJoinDP;
}
/ return a string for xform name
const CHAR *
SzId() const override
{
return "CXformExpandNAryJoinDP";
}
/ compute xform promise for a given expression handle
EXformPromise Exfp(CExpressionHandle &exprhdl) const override;
/ do stats need to be computed before applying xform?
BOOL
FNeedsStats() const override
{
return true;
}
/ actual transform
void Transform(CXformContext *pxfctxt, CXformResult *pxfres,
CExpression *pexpr) const override;
}; / class CXformExpandNAryJoinDP
} / namespace gpopt
#endif / !GPOPT_CXformExpandNAryJoinDP_H
/ EOF
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