greenplumn CXformGbAggWithMDQA2Join 代码
文件路径：/src/backend/gporca/libgpopt/src/xforms/CXformGbAggWithMDQA2Join.cpp
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2015 VMware, Inc. or its affiliates.
/
/ @filename:
/ CXformGbAggWithMDQA2Join.cpp
/
/ @doc:
/ Transform a GbAgg with multiple distinct qualified aggregates (MDQAs)
/ to a join tree with single DQA leaves
/---------------------------------------------------------------------------
#include "gpopt/xforms/CXformGbAggWithMDQA2Join.h"
#include "gpos/base.h"
#include "gpos/memory/CAutoMemoryPool.h"
#include "gpopt/base/CKeyCollection.h"
#include "gpopt/base/COptCtxt.h"
#include "gpopt/base/CUtils.h"
#include "gpopt/operators/CLogicalCTEAnchor.h"
#include "gpopt/operators/CLogicalCTEConsumer.h"
#include "gpopt/operators/CLogicalGbAgg.h"
#include "gpopt/operators/COperator.h"
#include "gpopt/xforms/CXformUtils.h"
using namespace gpmd;
using namespace gpopt;
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::CXformGbAggWithMDQA2Join
/
/ @doc:
/ Ctor
/
/---------------------------------------------------------------------------
CXformGbAggWithMDQA2Join::CXformGbAggWithMDQA2Join(CMemoryPool *mp)
: CXformExploration(
/ pattern
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalGbAgg(mp),
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CPatternTree(mp)), / relational child
GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CPatternTree(mp)) / scalar project list
))
{
}
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::Exfp
/
/ @doc:
/ Compute xform promise for a given expression handle;
/
/---------------------------------------------------------------------------
CXform::EXformPromise
CXformGbAggWithMDQA2Join::Exfp(CExpressionHandle &exprhdl) const
{
CAutoMemoryPool amp;
CLogicalGbAgg *popAgg = CLogicalGbAgg::PopConvert(exprhdl.Pop());
if (COperator::EgbaggtypeGlobal == popAgg->Egbaggtype() &&
exprhdl.DeriveHasMultipleDistinctAggs(1))
{
return CXform::ExfpHigh;
}
return CXform::ExfpNone;
}
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::PexprMDQAs2Join
/
/ @doc:
/ Converts GbAgg with multiple distinct aggregates into a join of single
/ distinct aggregates,
/
/ distinct aggregates that share the same argument are grouped together
/ in one leaf of the generated join expression,
/
/ non-distinct aggregates are also grouped together in one leaf of the
/ generated join expression
/
/---------------------------------------------------------------------------
CExpression *
CXformGbAggWithMDQA2Join::PexprMDQAs2Join(CMemoryPool *mp, CExpression *pexpr)
{
GPOS_ASSERT(nullptr != pexpr);
GPOS_ASSERT(COperator::EopLogicalGbAgg == pexpr->Pop()->Eopid());
GPOS_ASSERT((*pexpr)[1]->DeriveHasMultipleDistinctAggs());
/ extract components
CExpression *pexprChild = (*pexpr)[0];
CColRefSet *pcrsChildOutput = pexprChild->DeriveOutputColumns();
CColRefArray *pdrgpcrChildOutput = pcrsChildOutput->Pdrgpcr(mp);
/ create a CTE producer based on child expression
CCTEInfo *pcteinfo = COptCtxt::PoctxtFromTLS()->Pcteinfo();
const ULONG ulCTEId = pcteinfo->next_id();
(void) CXformUtils::PexprAddCTEProducer(mp, ulCTEId, pdrgpcrChildOutput,
pexprChild);
/ create a CTE consumer with child output columns
CExpression *pexprConsumer = GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalCTEConsumer(mp, ulCTEId, pdrgpcrChildOutput));
pcteinfo->IncrementConsumers(ulCTEId);
/ finalize GbAgg expression by replacing its child with CTE consumer
pexpr->Pop()->AddRef();
(*pexpr)[1]->AddRef();
CExpression *pexprGbAggWithConsumer =
GPOS_NEW(mp) CExpression(mp, pexpr->Pop(), pexprConsumer, (*pexpr)[1]);
CExpression *pexprJoinDQAs =
CXformUtils::PexprGbAggOnCTEConsumer2Join(mp, pexprGbAggWithConsumer);
GPOS_ASSERT(nullptr != pexprJoinDQAs);
pexprGbAggWithConsumer->Release();
return GPOS_NEW(mp) CExpression(
mp, GPOS_NEW(mp) CLogicalCTEAnchor(mp, ulCTEId), pexprJoinDQAs);
}
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::PexprExpandMDQAs
/
/ @doc:
/ Expand GbAgg with multiple distinct aggregates into a join of single
/ distinct aggregates,
/ return NULL if expansion is not done
/
/---------------------------------------------------------------------------
CExpression *
CXformGbAggWithMDQA2Join::PexprExpandMDQAs(CMemoryPool *mp, CExpression *pexpr)
{
GPOS_ASSERT(nullptr != pexpr);
GPOS_ASSERT(COperator::EopLogicalGbAgg == pexpr->Pop()->Eopid());
COperator *pop = pexpr->Pop();
if (CLogicalGbAgg::PopConvert(pop)->FGlobal())
{
BOOL fHasMultipleDistinctAggs =
(*pexpr)[1]->DeriveHasMultipleDistinctAggs();
if (fHasMultipleDistinctAggs)
{
CExpression *pexprExpanded = PexprMDQAs2Join(mp, pexpr);
/ recursively process the resulting expression
CExpression *pexprResult = PexprTransform(mp, pexprExpanded);
pexprExpanded->Release();
return pexprResult;
}
}
return nullptr;
}
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::PexprTransform
/
/ @doc:
/ Main transformation driver
/
/---------------------------------------------------------------------------
CExpression *
CXformGbAggWithMDQA2Join::PexprTransform(CMemoryPool *mp, CExpression *pexpr)
{
/ protect against stack overflow during recursion
GPOS_CHECK_STACK_SIZE;
GPOS_ASSERT(nullptr != mp);
GPOS_ASSERT(nullptr != pexpr);
COperator *pop = pexpr->Pop();
if (COperator::EopLogicalGbAgg == pop->Eopid())
{
CExpression *pexprResult = PexprExpandMDQAs(mp, pexpr);
if (nullptr != pexprResult)
{
return pexprResult;
}
}
/ recursively process child expressions
const ULONG arity = pexpr->Arity();
CExpressionArray *pdrgpexprChildren = GPOS_NEW(mp) CExpressionArray(mp);
for (ULONG ul = 0; ul < arity; ul++)
{
CExpression *pexprChild = PexprTransform(mp, (*pexpr)[ul]);
pdrgpexprChildren->Append(pexprChild);
}
pop->AddRef();
return GPOS_NEW(mp) CExpression(mp, pop, pdrgpexprChildren);
}
/---------------------------------------------------------------------------
/ @function:
/ CXformGbAggWithMDQA2Join::Transform
/
/ @doc:
/ Actual transformation to expand multiple distinct qualified aggregates
/ (MDQAs) to a join tree with single DQA leaves
/
/---------------------------------------------------------------------------
void
CXformGbAggWithMDQA2Join::Transform(CXformContext *pxfctxt,
CXformResult *pxfres,
CExpression *pexpr) const
{
GPOS_ASSERT(nullptr != pxfctxt);
GPOS_ASSERT(nullptr != pxfres);
GPOS_ASSERT(FPromising(pxfctxt->Pmp(), this, pexpr));
GPOS_ASSERT(FCheckPattern(pexpr));
CMemoryPool *mp = pxfctxt->Pmp();
CExpression *pexprResult = PexprTransform(mp, pexpr);
if (nullptr != pexprResult)
{
pxfres->Add(pexprResult);
}
}
BOOL
CXformGbAggWithMDQA2Join::IsApplyOnce()
{
return true;
}
/ EOF
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