C++ (Cpp) CXformContext Examples

Example #1

File: CSubqueryHandlerTest.cpp Project: b-xiang/gporca

//---------------------------------------------------------------------------
//	@function:
//		CSubqueryHandlerTest::EresUnittest_SubqueryWithConstSubqueries
//
//	@doc:
//		Test of subquery handler for ALL subquery over const table get
//
//---------------------------------------------------------------------------
GPOS_RESULT
CSubqueryHandlerTest::EresUnittest_SubqueryWithConstSubqueries()
{
	CAutoMemoryPool amp;
	IMemoryPool *mp = amp.Pmp();

	// setup a file-based provider
	CMDProviderMemory *pmdp = CTestUtils::m_pmdpf;
	pmdp->AddRef();
	
	// we need to use an auto pointer for the cache here to ensure
	// deleting memory of cached objects when we throw
	CAutoP<CMDAccessor::MDCache> apcache;
	apcache = CCacheFactory::CreateCache<gpopt::IMDCacheObject*, gpopt::CMDKey*>
					(
					true, // fUnique
					0 /* unlimited cache quota */,
					CMDKey::UlHashMDKey,
					CMDKey::FEqualMDKey
					);

	CMDAccessor::MDCache *pcache = apcache.Value();

	{
		CMDAccessor mda(mp, pcache, CTestUtils::m_sysidDefault, pmdp);

		// install opt context in TLS
		CAutoOptCtxt aoc
						(
						mp,
						&mda,
						NULL,  /* pceeval */
						CTestUtils::GetCostModel(mp)
						);

		// create a subquery with const table get expression
		CExpression *pexpr = CSubqueryTestUtils::PexprSubqueryWithDisjunction(mp);
		CXform *pxform = CXformFactory::Pxff()->Pxf(CXform::ExfSelect2Apply);

		CWStringDynamic str(mp);
		COstreamString oss(&str);

		oss	<< std::endl << "EXPRESSION:" << std::endl << *pexpr << std::endl;

		CExpression *pexprLogical = (*pexpr)[0];
		CExpression *pexprScalar = (*pexpr)[1];
		oss	<< std::endl << "LOGICAL:" << std::endl << *pexprLogical << std::endl;
		oss	<< std::endl << "SCALAR:" << std::endl << *pexprScalar << std::endl;

		GPOS_TRACE(str.GetBuffer());
		str.Reset();

		CXformContext *pxfctxt = GPOS_NEW(mp) CXformContext(mp);
		CXformResult *pxfres = GPOS_NEW(mp) CXformResult(mp);

		// calling the xform to perform subquery to Apply transformation;
		// xform must fail since we do not expect constant subqueries
		pxform->Transform(pxfctxt, pxfres, pexpr);
		CExpression *pexprResult = pxfres->PexprNext();
		
		oss	<< std::endl << "NEW LOGICAL:" << std::endl << *((*pexprResult)[0]) << std::endl;
		oss	<< std::endl << "RESIDUAL SCALAR:" << std::endl << *((*pexprResult)[1]) << std::endl;

		GPOS_TRACE(str.GetBuffer());
		str.Reset();

		pxfres->Release();
		pxfctxt->Release();
		pexpr->Release();
	
	}

	return GPOS_FAILED;
}

Example #2

File: CGroupExpression.cpp Project: HanumathRao/gporca

//---------------------------------------------------------------------------
//	@function:
//		CGroupExpression::Transform
//
//	@doc:
//		Transform group expression using the given xform
//
//---------------------------------------------------------------------------
void
CGroupExpression::Transform
	(
	IMemoryPool *pmp,
	IMemoryPool *pmpLocal,
	CXform *pxform,
	CXformResult *pxfres,
	ULONG *pulElapsedTime // output: elapsed time in millisecond
	)
{
	GPOS_ASSERT(NULL != pulElapsedTime);
	GPOS_CHECK_ABORT;

	CTimerUser timer;

	// check traceflag and compatibility with origin xform
	if (GPOPT_FDISABLED_XFORM(pxform->Exfid())|| !pxform->FCompatible(m_exfidOrigin))
	{
		*pulElapsedTime = timer.UlElapsedMS();
		return;
	}

	// check xform promise
	CExpressionHandle exprhdl(pmp);
	exprhdl.Attach(this);
	exprhdl.DeriveProps(NULL /*pdpctxt*/);
	if (CXform::ExfpNone == pxform->Exfp(exprhdl))
	{
		*pulElapsedTime = timer.UlElapsedMS();
		return;
	}

	// pre-processing before applying xform to group expression
	PreprocessTransform(pmpLocal, pmp, pxform);

	// extract memo bindings to apply xform
	CBinding binding;
	CXformContext *pxfctxt = GPOS_NEW(pmp) CXformContext(pmp);

	CExpression *pexprPattern = pxform->PexprPattern();
	CExpression *pexpr = binding.PexprExtract(pmp, this, pexprPattern , NULL);
	while (NULL != pexpr)
	{
		pxform->Transform(pxfctxt, pxfres, pexpr);
		PrintXform(pmp, pxform, pexpr, pxfres);

		if (CXformUtils::FApplyOnce(pxform->Exfid()) ||
			(0 < pxfres->Pdrgpexpr()->UlLength() &&
			!CXformUtils::FApplyToNextBinding(pxform, pexpr)))
		{
			// do not apply xform to other possible patterns
			pexpr->Release();
			break;
		}

		CExpression *pexprLast = pexpr;
		pexpr = binding.PexprExtract(pmp, this, pexprPattern, pexprLast);

		// release last extracted expression
		pexprLast->Release();

		GPOS_CHECK_ABORT;
	}
	pxfctxt->Release();

	// post-prcoessing before applying xform to group expression
	PostprocessTransform(pmpLocal, pmp, pxform);

	*pulElapsedTime = timer.UlElapsedMS();
}