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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