I don't understand why.
loadMetadata(global_context, default_database);
        startupSystemTables();
        database_catalog.loadDatabases();
        
        database_catalog.assertDatabaseExists(default_database);
    }
    catch (...)
    {
        tryLogCurrentException(log, "Caught exception while loading metadata");
        throw;
    }
    LOG_DEBUG(log, "Loaded metadata.");
    
    
#if USE_UNWIND && !WITH_COVERAGE && defined(__x86_64__)
    
    if (hasPHDRCache())
    {
        global_context->initializeTraceCollector();
        
        UInt64 total_memory_profiler_step = config().getUInt64("total_memory_profiler_step", 0);
        if (total_memory_profiler_step)
        {
            total_memory_tracker.setProfilerStep(total_memory_profiler_step);
        }
        double total_memory_tracker_sample_probability = config().getDouble("total_memory_tracker_sample_probability", 0);
        if (total_memory_tracker_sample_probability)
        {
            total_memory_tracker.setSampleProbability(total_memory_tracker_sample_probability);