nest7_issue.cs

    ...
    Parallel.ForEach(divisions,
    	new ParallelOptions { MaxDegreeOfParallelism = 5 },
    	division => _loaderFactory.Create().Load(division)
    );
    ...
    
    public virtual void Load(DivisionDto division)
    {
    	var sqlRecords = GetSqlRecords(division);
    	if (sqlRecords.Length == 0) return;
    
    	var bulkCollection = new ConcurrentDictionary<string, Team>();
    	const int pageSize = 300;
    
    	var pages = Paginator.ConvertToPages(sqlRecords.Length, pageSize);
    
    	Parallel.ForEach(Enumerable.Range(0, pages), new ParallelOptions {MaxDegreeOfParallelism = 20}, page =>
    	{
    		var batch = sqlRecords.Skip(page * pageSize).Take(pageSize).ToArray();
    
    		GetUpdatedCollection(division, batch, bulkCollection);
    	});
    	if (bulkCollection.Count > 0) _repository.UpdateAll(bulkCollection.Values, division, onVersionConflictFn);
    }
    
    private void GetUpdatedCollection(DivisionDto division, GameEvent[] batch, ConcurrentDictionary<string, Team> bulkCollection)
    {
    	var teams = _repository.FindByGames(batch, division);
    	teams.ForEach(team =>
    	{
    		// mutation logic
    		// adding to bulkCollection
    	});
    }
    
    public IEnumerable<Team> FindByGames(IEnumerable<GameEvent> facts, DivisionDto division)
    {
    	_indexName = _indexNameGenerator.GetIndexName(division);
    	return Search(q => MatchByGames(facts));
    }
    
    private static QueryContainer MatchByGames(IEnumerable<GameEvent> facts)
    {
    	var factIds = facts.Select(f => f.cId as object).AsEnumerable();
    	return Query<Team>.Bool(b => b.Must(new QueryContainer(new TermsQuery {Field = "cIds", Terms = factIds})));
    	So basically terms will contain 300 values
    }
    
    private IEnumerable<Team> Search(Func<QueryContainerDescriptor<GameEvent>, QueryContainer> query)
    {
    	var sw = new Stopwatch();
    	sw.Start();
    	EXCEPTION HAPPENS ON NEXT LINE 
    	var response = _esClient.Search<Team>(s => s.Index(_indexName).Size(10000).Query(query).Version().SequenceNumberPrimaryTerm());
    	sw.Stop();
    	_logger.Info($"network + parsing time: {sw.ElapsedMilliseconds}ms. es side time: {response.Took}ms. records found: {response.HitsMetadata?.Total.Value} records returned: {response.Total}; response text length: {response.DebugInformation?.Length}");
    
    	// mapping logic and return
    }