greenplumn CPartialPlan 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/engine/CPartialPlan.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2014 VMware, Inc. or its affiliates.
/
/ @filename:
/ CPartialPlan.h
/
/ @doc:
/
/ A partial plan is a group expression where none (or not all) of its
/ optimal child plans are discovered yet,
/ by assuming the smallest possible cost of unknown child plans, a partial
/ plan's cost gives a lower bound on the cost of the corresponding complete plan,
/ this information is used to prune the optimization search space during branch
/ and bound search
/---------------------------------------------------------------------------
#ifndef GPOPT_CPartialPlan_H
#define GPOPT_CPartialPlan_H
#include "gpos/base.h"
#include "gpos/common/CRefCount.h"
#include "gpopt/base/CReqdProp.h"
#include "gpopt/cost/ICostModel.h"
namespace gpopt
{
using namespace gpos;
class CGroupExpression;
class CCost;
class CCostContext;
/---------------------------------------------------------------------------
/ @class:
/ CPartialPlan
/
/ @doc:
/ Description of partial plans created during optimization
/
/---------------------------------------------------------------------------
class CPartialPlan : public CRefCount
{
private:
/ root group expression
CGroupExpression *m_pgexpr;
/ required plan properties of root operator
CReqdPropPlan *m_prpp;
/ cost context of known child plan -- can be null if no child plans are known
CCostContext *m_pccChild;
/ index of known child plan
ULONG m_ulChildIndex;
/ extract costing info from children
void ExtractChildrenCostingInfo(CMemoryPool *mp, ICostModel *pcm,
CExpressionHandle &exprhdl,
ICostModel::SCostingInfo *pci);
public:
CPartialPlan(const CPartialPlan &) = delete;
/ ctor
CPartialPlan(CGroupExpression *pgexpr, CReqdPropPlan *prpp,
CCostContext *pccChild, ULONG child_index);
/ dtor
~CPartialPlan() override;
/ group expression accessor
CGroupExpression *
Pgexpr() const
{
return m_pgexpr;
}
/ plan properties accessor
CReqdPropPlan *
Prpp() const
{
return m_prpp;
}
/ child cost context accessor
CCostContext *
PccChild() const
{
return m_pccChild;
}
/ child index accessor
ULONG
UlChildIndex() const
{
return m_ulChildIndex;
}
/ compute partial plan cost
CCost CostCompute(CMemoryPool *mp);
/ hash function used for cost bounding
static ULONG HashValue(const CPartialPlan *ppp);
/ equality function used for for cost bounding
static BOOL Equals(const CPartialPlan *pppFst, const CPartialPlan *pppSnd);
}; / class CPartialPlan
} / namespace gpopt
#endif / !GPOPT_CPartialPlan_H
/ EOF