greenplumn CXformSimplifyProjectWithSubquery 源码
greenplumn CXformSimplifyProjectWithSubquery 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/xforms/CXformSimplifyProjectWithSubquery.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2012 EMC Corp.
//
// @filename:
// CXformSimplifyProjectWithSubquery.h
//
// @doc:
// Simplify Project with subquery
//---------------------------------------------------------------------------
#ifndef GPOPT_CXformSimplifyProjectWithSubquery_H
#define GPOPT_CXformSimplifyProjectWithSubquery_H
#include "gpos/base.h"
#include "gpopt/operators/CExpression.h"
#include "gpopt/operators/CLogicalProject.h"
#include "gpopt/operators/CPatternLeaf.h"
#include "gpopt/xforms/CXformSimplifySubquery.h"
namespace gpopt
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// CXformSimplifyProjectWithSubquery
//
// @doc:
// Simplify Project with subquery
//
//---------------------------------------------------------------------------
class CXformSimplifyProjectWithSubquery : public CXformSimplifySubquery
{
private:
public:
CXformSimplifyProjectWithSubquery(
const CXformSimplifyProjectWithSubquery &) = delete;
// ctor
explicit CXformSimplifyProjectWithSubquery(CMemoryPool *mp)
: // pattern
CXformSimplifySubquery(GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalProject(mp),
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CPatternLeaf(mp)), // relational child
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CPatternTree(mp)) // project list
))
{
}
// dtor
~CXformSimplifyProjectWithSubquery() override = default;
// Compatibility function for simplifying aggregates
BOOL
FCompatible(CXform::EXformId exfid) override
{
return (CXform::ExfSimplifyProjectWithSubquery != exfid);
}
// ident accessors
EXformId
Exfid() const override
{
return ExfSimplifyProjectWithSubquery;
}
// return a string for xform name
const CHAR *
SzId() const override
{
return "CXformSimplifyProjectWithSubquery";
}
// is transformation a subquery unnesting (Subquery To Apply) xform?
BOOL
FSubqueryUnnesting() const override
{
return true;
}
}; // class CXformSimplifyProjectWithSubquery
} // namespace gpopt
#endif // !GPOPT_CXformSimplifyProjectWithSubquery_H
// EOF
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