greenplumn CXformCTEAnchor2Sequence 代码
文件路径：/src/backend/gporca/libgpopt/src/xforms/CXformCTEAnchor2Sequence.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CXformCTEAnchor2Sequence.cpp
/
/ @doc:
/ Implementation of transform
/---------------------------------------------------------------------------
#include "gpopt/xforms/CXformCTEAnchor2Sequence.h"
#include "gpos/base.h"
#include "gpopt/base/COptCtxt.h"
#include "gpopt/operators/CLogicalCTEAnchor.h"
#include "gpopt/operators/CLogicalSequence.h"
#include "gpopt/operators/CPatternLeaf.h"
#include "gpopt/xforms/CXformUtils.h"
using namespace gpopt;
/---------------------------------------------------------------------------
/ @function:
/ CXformCTEAnchor2Sequence::CXformCTEAnchor2Sequence
/
/ @doc:
/ Ctor
/
/---------------------------------------------------------------------------
CXformCTEAnchor2Sequence::CXformCTEAnchor2Sequence(CMemoryPool *mp)
: CXformExploration(
/ pattern
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalCTEAnchor(mp),
GPOS_NEW(mp) CExpression(mp, GPOS_NEW(mp) CPatternLeaf(mp))))
{
}
/---------------------------------------------------------------------------
/ @function:
/ CXformCTEAnchor2Sequence::Exfp
/
/ @doc:
/ Compute promise of xform
/
/---------------------------------------------------------------------------
CXform::EXformPromise
CXformCTEAnchor2Sequence::Exfp(CExpressionHandle &exprhdl) const
{
ULONG id = CLogicalCTEAnchor::PopConvert(exprhdl.Pop())->Id();
const ULONG ulConsumers =
COptCtxt::PoctxtFromTLS()->Pcteinfo()->UlConsumers(id);
GPOS_ASSERT(0 < ulConsumers);
if (1 == ulConsumers && CXformUtils::FInlinableCTE(id))
{
return CXform::ExfpNone;
}
return CXform::ExfpHigh;
}
/---------------------------------------------------------------------------
/ @function:
/ CXformCTEAnchor2Sequence::Transform
/
/ @doc:
/ Actual transformation
/
/---------------------------------------------------------------------------
void
CXformCTEAnchor2Sequence::Transform(CXformContext *pxfctxt,
CXformResult *pxfres,
CExpression *pexpr) const
{
GPOS_ASSERT(nullptr != pxfctxt);
GPOS_ASSERT(FPromising(pxfctxt->Pmp(), this, pexpr));
GPOS_ASSERT(FCheckPattern(pexpr));
/ ExfExpandFullOuterJoin converts a LogicalFullJoin to a CTE with a UnionAll
/ of an LOJ and LASJ. Even if expansion is disabled by the trace flag, the
/ xform still needs to be triggered, so that the CTE operator generated
/ can be used to compute the statistics for the logical merge join group (see
/ CLogicalFullOuterJoin::Esp()).
/ Instead, we skip the implementation of the CTE, here, if the trace flag is
/ disabled and the CTE op was generated by ExfExpandFullOuterJoin.
CGroupExpression *pgexprOrigin = pexpr->Pgexpr();
if (!GPOS_FTRACE(EopttraceExpandFullJoin) && nullptr != pgexprOrigin &&
CXform::ExfExpandFullOuterJoin == pgexprOrigin->ExfidOrigin())
{
return;
}
CLogicalCTEAnchor *popCTEAnchor =
CLogicalCTEAnchor::PopConvert(pexpr->Pop());
CMemoryPool *mp = pxfctxt->Pmp();
ULONG id = popCTEAnchor->Id();
CExpression *pexprProducer =
COptCtxt::PoctxtFromTLS()->Pcteinfo()->PexprCTEProducer(id);
GPOS_ASSERT(nullptr != pexprProducer);
pexprProducer->AddRef();
/ child of CTE anchor
CExpression *pexprChild = (*pexpr)[0];
pexprChild->AddRef();
/ create logical sequence
CExpression *pexprSequence = GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalSequence(mp), pexprProducer, pexprChild);
pxfres->Add(pexprSequence);
}
/ EOF
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