greenplumn CDXLLogicalLimit 源码
greenplumn CDXLLogicalLimit 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/dxl/operators/CDXLLogicalLimit.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 EMC Corp.
//
// @filename:
// CDXLLogicalLimit.h
//
// @doc:
// Class for representing DXL logical limit operators
//
//---------------------------------------------------------------------------
#ifndef GPDXL_CDXLLogicalLimit_H
#define GPDXL_CDXLLogicalLimit_H
#include "gpos/base.h"
#include "naucrates/dxl/operators/CDXLLogical.h"
#include "naucrates/dxl/operators/CDXLNode.h"
namespace gpdxl
{
// indices of limit elements in the children array
enum EdxlLogicalLimit
{
EdxllogicallimitIndexSortColList = 0,
EdxllogicallimitIndexLimitCount,
EdxllogicallimitIndexLimitOffset,
EdxllogicallimitIndexChildPlan
};
//---------------------------------------------------------------------------
// @class:
// CDXLLogicalLimit
//
// @doc:
// Class for representing DXL Logical limit operators
//
//---------------------------------------------------------------------------
class CDXLLogicalLimit : public CDXLLogical
{
private:
BOOL m_top_limit_under_dml;
public:
CDXLLogicalLimit(CDXLLogicalLimit &) = delete;
// ctor/dtor
CDXLLogicalLimit(CMemoryPool *mp, BOOL fNonRemovableLimit);
~CDXLLogicalLimit() override;
// accessors
Edxlopid GetDXLOperator() const override;
const CWStringConst *GetOpNameStr() const override;
// the limit is right under a DML or CTAS
BOOL
IsTopLimitUnderDMLorCTAS() const
{
return m_top_limit_under_dml;
}
// serialize operator in DXL format
void SerializeToDXL(CXMLSerializer *xml_serializer,
const CDXLNode *node) const override;
// conversion function
static CDXLLogicalLimit *
Cast(CDXLOperator *dxl_op)
{
GPOS_ASSERT(nullptr != dxl_op);
GPOS_ASSERT(EdxlopLogicalLimit == dxl_op->GetDXLOperator());
return dynamic_cast<CDXLLogicalLimit *>(dxl_op);
}
#ifdef GPOS_DEBUG
// checks whether the operator has valid structure, i.e. number and
// types of child nodes
void AssertValid(const CDXLNode *, BOOL validate_children) const override;
#endif // GPOS_DEBUG
};
} // namespace gpdxl
#endif // !GPDXL_CDXLLogicalLimit_H
// EOF
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