Question

I use SQL Server. I got a large table – millions of rows. And I iterate through them (SELECT .. WHERE ..). This is a long operation (and I assume can’t be shorter).

So what am I asking is if there will be any problems to insert data into that table in the progress of selecting? If yes, what should I do to reduce that? Same questing for update command (with indexed parameters of course).

Answer 1

The answer is yes, absolutely. A simple solution (if it’s an acceptable trade off within your application) is to specify the NOLOCK locking hint. IE:

select * from table with NOLOCK

The tradeoff is that you won’t get a consistent read, but in many cases this isn’t problem.