Method OptimizeTask

src/backend/gpopt/utils/COptTasks.cpp:882–1037

--------------------------------------------------------------------------- @function: COptTasks::OptimizeTask @doc: task that does the optimizes query to physical DXL ---------------------------------------------------------------------------

//
//---------------------------------------------------------------------------
void *
COptTasks::OptimizeTask(void *ptr)
{
	GPOS_ASSERT(nullptr != ptr);
	SOptContext *opt_ctxt = SOptContext::Cast(ptr);

	GPOS_ASSERT(nullptr != opt_ctxt->m_query);
	GPOS_ASSERT(nullptr == opt_ctxt->m_plan_dxl);
	GPOS_ASSERT(nullptr == opt_ctxt->m_plan_stmt);

	AUTO_MEM_POOL(amp);
	CMemoryPool *mp = amp.Pmp();

	// Does the metadatacache need to be reset?
	//
	// On the first call, before the cache has been initialized, we
	// don't care about the return value of MDCacheNeedsReset(). But
	// we need to call it anyway, to give it a chance to initialize
	// the invalidation mechanism.
	bool reset_mdcache = gpdb::MDCacheNeedsReset();

	// initialize metadata cache, or purge if needed, or change size if requested
	if (!CMDCache::FInitialized())
	{
		CMDCache::Init();
		CMDCache::SetCacheQuota(optimizer_mdcache_size * 1024L);
	}
	else if (reset_mdcache)
	{
		CMDCache::Reset();
		CMDCache::SetCacheQuota(optimizer_mdcache_size * 1024L);
	}
	else if (CMDCache::ULLGetCacheQuota() !=
			 (ULLONG) optimizer_mdcache_size * 1024L)
	{
		CMDCache::SetCacheQuota(optimizer_mdcache_size * 1024L);
	}


	// load search strategy
	CSearchStageArray *search_strategy_arr =
		LoadSearchStrategy(mp, optimizer_search_strategy_path);

	CBitSet *trace_flags = nullptr;
	CBitSet *enabled_trace_flags = nullptr;
	CBitSet *disabled_trace_flags = nullptr;
	CDXLNode *plan_dxl = nullptr;

	IMdIdArray *col_stats = nullptr;
	MdidHashSet *rel_stats = nullptr;

	GPOS_TRY
	{
		// set trace flags
		trace_flags = CConfigParamMapping::PackConfigParamInBitset(
			mp, CXform::ExfSentinel, opt_ctxt->m_create_vec_plan);
		SetTraceflags(mp, trace_flags, &enabled_trace_flags,
					  &disabled_trace_flags);