greenplumn CXformUpdate2DML 源码

greenplumn CXformUpdate2DML 代码

文件路径：/src/backend/gporca/libgpopt/src/xforms/CXformUpdate2DML.cpp

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2012 EMC Corp.
//
//	@filename:
//		CXformUpdate2DML.cpp
//
//	@doc:
//		Implementation of transform
//---------------------------------------------------------------------------

#include "gpopt/xforms/CXformUpdate2DML.h"

#include "gpos/base.h"

#include "gpopt/metadata/CTableDescriptor.h"
#include "gpopt/operators/CLogicalPartitionSelector.h"
#include "gpopt/operators/CLogicalSplit.h"
#include "gpopt/operators/CLogicalUpdate.h"
#include "gpopt/operators/CPatternLeaf.h"
#include "gpopt/operators/CScalarDMLAction.h"
#include "gpopt/operators/CScalarProjectElement.h"
#include "gpopt/operators/CScalarProjectList.h"
#include "gpopt/optimizer/COptimizerConfig.h"
#include "gpopt/xforms/CXformUtils.h"
#include "naucrates/md/IMDTypeInt4.h"

using namespace gpopt;


//---------------------------------------------------------------------------
//	@function:
//		CXformUpdate2DML::CXformUpdate2DML
//
//	@doc:
//		Ctor
//
//---------------------------------------------------------------------------
CXformUpdate2DML::CXformUpdate2DML(CMemoryPool *mp)
	: CXformExploration(
		  // pattern
		  GPOS_NEW(mp) CExpression(
			  mp, GPOS_NEW(mp) CLogicalUpdate(mp),
			  GPOS_NEW(mp) CExpression(mp, GPOS_NEW(mp) CPatternLeaf(mp))))
{
}

//---------------------------------------------------------------------------
//	@function:
//		CXformUpdate2DML::Exfp
//
//	@doc:
//		Compute promise of xform
//
//---------------------------------------------------------------------------
CXform::EXformPromise
CXformUpdate2DML::Exfp(CExpressionHandle &	// exprhdl
) const
{
	return CXform::ExfpHigh;
}

//---------------------------------------------------------------------------
//	@function:
//		CXformUpdate2DML::Transform
//
//	@doc:
//		Actual transformation
//
//---------------------------------------------------------------------------
void
CXformUpdate2DML::Transform(CXformContext *pxfctxt, CXformResult *pxfres,
							CExpression *pexpr) const
{
	GPOS_ASSERT(nullptr != pxfctxt);
	GPOS_ASSERT(FPromising(pxfctxt->Pmp(), this, pexpr));
	GPOS_ASSERT(FCheckPattern(pexpr));

	CLogicalUpdate *popUpdate = CLogicalUpdate::PopConvert(pexpr->Pop());
	CMemoryPool *mp = pxfctxt->Pmp();

	// extract components for alternative

	CTableDescriptor *ptabdesc = popUpdate->Ptabdesc();
	CColRefArray *pdrgpcrDelete = popUpdate->PdrgpcrDelete();
	CColRefArray *pdrgpcrInsert = popUpdate->PdrgpcrInsert();
	CColRef *pcrCtid = popUpdate->PcrCtid();
	CColRef *pcrSegmentId = popUpdate->PcrSegmentId();
	BOOL fSplit = popUpdate->FSplit();

	// child of update operator
	CExpression *pexprChild = (*pexpr)[0];
	pexprChild->AddRef();

	IMDId *rel_mdid = ptabdesc->MDId();
	if (CXformUtils::FTriggersExist(CLogicalDML::EdmlUpdate, ptabdesc,
									true /*fBefore*/))
	{
		rel_mdid->AddRef();
		pdrgpcrDelete->AddRef();
		pdrgpcrInsert->AddRef();
		pexprChild = CXformUtils::PexprRowTrigger(
			mp, pexprChild, CLogicalDML::EdmlUpdate, rel_mdid, true /*fBefore*/,
			pdrgpcrDelete, pdrgpcrInsert);
	}

	// generate the action column and split operator
	COptCtxt *poctxt = COptCtxt::PoctxtFromTLS();
	CMDAccessor *md_accessor = poctxt->Pmda();
	CColumnFactory *col_factory = poctxt->Pcf();

	const IMDType *pmdtype = md_accessor->PtMDType<IMDTypeInt4>();
	CColRef *pcrAction = col_factory->PcrCreate(pmdtype, default_type_modifier);

	CExpression *pexprSplit = nullptr;
	if (fSplit)
	{
		pdrgpcrDelete->AddRef();
		pdrgpcrInsert->AddRef();
		CExpression *pexprProjElem = GPOS_NEW(mp) CExpression(
			mp, GPOS_NEW(mp) CScalarProjectElement(mp, pcrAction),
			GPOS_NEW(mp) CExpression(mp, GPOS_NEW(mp) CScalarDMLAction(mp)));

		CExpression *pexprProjList = GPOS_NEW(mp)
			CExpression(mp, GPOS_NEW(mp) CScalarProjectList(mp), pexprProjElem);
		pexprSplit = GPOS_NEW(mp) CExpression(
			mp,
			GPOS_NEW(mp) CLogicalSplit(mp, pdrgpcrDelete, pdrgpcrInsert,
									   pcrCtid, pcrSegmentId, pcrAction),
			pexprChild, pexprProjList);
	}
	else
	{
		pexprSplit = pexprChild;
	}


	// add assert checking that no NULL values are inserted for nullable columns or no check constraints are violated
	COptimizerConfig *optimizer_config =
		COptCtxt::PoctxtFromTLS()->GetOptimizerConfig();
	CExpression *pexprAssertConstraints;
	if (optimizer_config->GetHint()->FEnforceConstraintsOnDML())
	{
		pexprAssertConstraints = CXformUtils::PexprAssertConstraints(
			mp, pexprSplit, ptabdesc, pdrgpcrInsert);
	}
	else
	{
		pexprAssertConstraints = pexprSplit;
	}

	// generate oid column and project operator
	CExpression *pexprProject = nullptr;
	CColRef *pcrTableOid = nullptr;
	if (ptabdesc->IsPartitioned())
	{
		// generate a partition selector
		pexprProject = CXformUtils::PexprLogicalPartitionSelector(
			mp, ptabdesc, pdrgpcrInsert, pexprAssertConstraints);
		pcrTableOid = CLogicalPartitionSelector::PopConvert(pexprProject->Pop())
						  ->PcrOid();
	}
	else
	{
		// generate a project operator
		IMDId *pmdidTable = ptabdesc->MDId();

		OID oidTable = CMDIdGPDB::CastMdid(pmdidTable)->Oid();
		CExpression *pexprOid = CUtils::PexprScalarConstOid(mp, oidTable);

		pexprProject =
			CUtils::PexprAddProjection(mp, pexprAssertConstraints, pexprOid);

		CExpression *pexprPrL = (*pexprProject)[1];
		pcrTableOid = CUtils::PcrFromProjElem((*pexprPrL)[0]);
	}

	GPOS_ASSERT(nullptr != pcrTableOid);

	const ULONG num_cols = pdrgpcrInsert->Size();

	CExpression *pexprDML = nullptr;
	// create logical DML
	ptabdesc->AddRef();
	if (fSplit)
	{
		CBitSet *pbsModified =
			GPOS_NEW(mp) CBitSet(mp, ptabdesc->ColumnCount());
		for (ULONG ul = 0; ul < num_cols; ul++)
		{
			CColRef *pcrInsert = (*pdrgpcrInsert)[ul];
			CColRef *pcrDelete = (*pdrgpcrDelete)[ul];
			if (pcrInsert != pcrDelete)
			{
				// delete columns refer to the original tuple's descriptor, if it's different
				// from the corresponding insert column, then we're modifying the column
				// at that position
				pbsModified->ExchangeSet(ul);
			}
		}
		pdrgpcrDelete->AddRef();
		pexprDML = GPOS_NEW(mp) CExpression(
			mp,
			GPOS_NEW(mp)
				CLogicalDML(mp, CLogicalDML::EdmlUpdate, ptabdesc,
							pdrgpcrDelete, pbsModified, pcrAction, pcrTableOid,
							pcrCtid, pcrSegmentId, fSplit),
			pexprProject);
	}
	else
	{
		pdrgpcrInsert->AddRef();
		pexprDML = GPOS_NEW(mp) CExpression(
			mp,
			GPOS_NEW(mp)
				CLogicalDML(mp, CLogicalDML::EdmlUpdate, ptabdesc,
							pdrgpcrInsert, GPOS_NEW(mp) CBitSet(mp), pcrAction,
							pcrTableOid, pcrCtid, pcrSegmentId, fSplit),
			pexprProject);
	}

	// TODO:  - Oct 30, 2012; detect and handle AFTER triggers on update

	pxfres->Add(pexprDML);
}

// EOF

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