throw; throw ex; optimal

Question

Possible Duplicate:
.NET - Throwing Exceptions best practices

Hi,

I have seen people re-throwing exceptions as given below. which one is optimal? Why one mechanism is optimal than the other one.

try
{
   // do something
}
catch (exception ex)
{
   // do something
   throw ex;
}

---

try
{
    // do something
}
catch (exception ex)
{
   // do something
   throw;
}

Answer 1

well, I don't know about others, but sometimes we do the second method to log the error and then catch it somewhere else.