You can only have a maximum of X many threads on windows systems. The default virtual space a thread consumes is 1Meg, and if you're not careful, your pc could end up being very busy for a long time. I suggest you create as few threads as possible, only use them when there's no way around, such as a database query. But even so you only need one extra thread for an unlimited amount of database connection. Pending queries may be stacked. I'm not sure what you mean with "data_locked", AFAIK you don't need to lock anything.