greenplumn CXformGbAggWithMDQA2Join 源码
greenplumn CXformGbAggWithMDQA2Join 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/xforms/CXformGbAggWithMDQA2Join.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2015 VMware, Inc. or its affiliates.
//
// @filename:
// CXformGbAggWithMDQA2Join.h
//
// @doc:
// Transform a GbAgg with multiple distinct qualified aggregates (MDQAs)
// to a join tree with single DQA leaves
//---------------------------------------------------------------------------
#ifndef GPOPT_CXformGbAggWithMDQA2Join_H
#define GPOPT_CXformGbAggWithMDQA2Join_H
#include "gpos/base.h"
#include "gpopt/xforms/CXformExploration.h"
namespace gpopt
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// CXformGbAggWithMDQA2Join
//
// @doc:
// Transform a GbAgg with multiple distinct qualified aggregates (MDQAs)
// to a join tree with single DQA leaves
//
//---------------------------------------------------------------------------
class CXformGbAggWithMDQA2Join : public CXformExploration
{
private:
static CExpression *PexprMDQAs2Join(CMemoryPool *mp, CExpression *pexpr);
// expand GbAgg with multiple distinct aggregates into a join of single distinct
// aggregates
static CExpression *PexprExpandMDQAs(CMemoryPool *mp, CExpression *pexpr);
// main transformation function driver
static CExpression *PexprTransform(CMemoryPool *mp, CExpression *pexpr);
public:
CXformGbAggWithMDQA2Join(const CXformGbAggWithMDQA2Join &) = delete;
// ctor
explicit CXformGbAggWithMDQA2Join(CMemoryPool *mp);
// dtor
~CXformGbAggWithMDQA2Join() override = default;
// ident accessors
EXformId
Exfid() const override
{
return ExfGbAggWithMDQA2Join;
}
// return a string for xform name
const CHAR *
SzId() const override
{
return "CXformGbAggWithMDQA2Join";
}
// compute xform promise for a given expression handle
EXformPromise Exfp(CExpressionHandle &exprhdl) const override;
// actual transform
void Transform(CXformContext *, CXformResult *,
CExpression *) const override;
// return true if xform should be applied only once
BOOL IsApplyOnce() override;
}; // class CXformGbAggWithMDQA2Join
} // namespace gpopt
#endif // !GPOPT_CXformGbAggWithMDQA2Join_H
// EOF
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