C++ (Cpp) CJob::UlpRefs Examples

Example #1

File: CScheduler.cpp Project: MoZhonghua/gporca

//---------------------------------------------------------------------------
//	@function:
//		CScheduler::PjRetrieve
//
//	@doc:
//		Retrieve next runnable job from queue
//
//---------------------------------------------------------------------------
CJob *
CScheduler::PjRetrieve()
{
#ifdef GPOS_DEBUG
	// restrict parallelism to keep track of jobs
	CAutoMutex am(m_mutex);
	if (FTrackingJobs())
	{
		am.Lock();
	}
#endif // GPOS_DEBUG

	// retrieve runnable job from lists of waiting jobs
	SJobLink *pjl = m_listjlWaiting.Pop();
	CJob *pj = NULL;

	if (NULL != pjl)
	{
		pj = pjl->m_pj;

		GPOS_ASSERT(NULL != pj);
		GPOS_ASSERT(0 == pj->UlpRefs());

		// decrement number of queued jobs
		(void) UlpExchangeAdd(&m_ulpQueued, -1);

		// update statistics
		(void) UlpExchangeAdd(&m_ulpStatsDequeued, 1);

		// recycle job link
		m_spjl.Recycle(pjl);

#ifdef GPOS_DEBUG
		// add job to running list
		if (FTrackingJobs())
		{
			GPOS_ASSERT(CJob::EjsWaiting == pj->Ejs());

			pj->SetState(CJob::EjsRunning);
			m_listjRunning.Append(pj);
		}
#endif // GPOS_DEBUG
	}
	
	return pj;
}