sql nhibernate的性能循环

Question

I have the following logic:

loop through a list of ids, get the associated entity, and for that entity, loop through another list of ids and get another entity. Code is below:

foreach (var docId in docIds)
{
      var doc = new EntityManager<Document>().GetById(docId);
      foreach (var tradeId in tradeIds)
      {
          var trade = new EntityManager<Trade>().GetById(tradeId);
          if (doc.Trade.TradeId != trade.TradeId)
          {
              Document newDoc = new Document(doc, trade, 0);
              new EntityManager<Document>().Add(newDoc);
          }
      }
}

my question is mainly about sql performance. Obviously there will be a bunch of selects happening, as well as some adds . Is this a bad way to go about doing something like this?

Should I, instead, use a session and get a list of all entities that match the list of ids (with 1 select statement) and then loop after?

Answer 1

It depends only on my expirience. But you can test it yourselve. If Trade entity isn't very big and count of entities wouldnt be over 1000 - reading all entities and loop after will be much preferable. If count is more 1k - its better to call stored procedure with joining temp table, containing your ids.