greenplumn CXformSimplifyGbAgg 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/xforms/CXformSimplifyGbAgg.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CXformSimplifyGbAgg.h
/
/ @doc:
/ Simplify an aggregate by splitting grouping columns into a set of
/ functional dependencies in preparation for pushing Gb below join
/---------------------------------------------------------------------------
#ifndef GPOPT_CXformSimplifyGbAgg_H
#define GPOPT_CXformSimplifyGbAgg_H
#include "gpos/base.h"
#include "gpopt/xforms/CXformExploration.h"
namespace gpopt
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CXformSimplifyGbAgg
/
/ @doc:
/ Simplify an aggregate by splitting grouping columns into a set of
/ functional dependencies
/
/---------------------------------------------------------------------------
class CXformSimplifyGbAgg : public CXformExploration
{
private:
/ helper to check if GbAgg can be transformed to a Select
static BOOL FDropGbAgg(CMemoryPool *mp, CExpression *pexpr,
CXformResult *pxfres);
public:
CXformSimplifyGbAgg(const CXformSimplifyGbAgg &) = delete;
/ ctor
explicit CXformSimplifyGbAgg(CMemoryPool *mp);
/ dtor
~CXformSimplifyGbAgg() override = default;
/ ident accessors
EXformId
Exfid() const override
{
return ExfSimplifyGbAgg;
}
/ return a string for xform name
const CHAR *
SzId() const override
{
return "CXformSimplifyGbAgg";
}
/ Compatibility function for simplifying aggregates
BOOL
FCompatible(CXform::EXformId exfid) override
{
return (CXform::ExfSimplifyGbAgg != exfid) &&
(CXform::ExfSplitDQA != exfid) &&
(CXform::ExfSplitGbAgg != exfid) &&
(CXform::ExfEagerAgg != exfid);
}
/ compute xform promise for a given expression handle
EXformPromise Exfp(CExpressionHandle &exprhdl) const override;
/ actual transform
void Transform(CXformContext *, CXformResult *,
CExpression *) const override;
}; / class CXformSimplifyGbAgg
} / namespace gpopt
#endif / !GPOPT_CXformSimplifyGbAgg_H
/ EOF
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