MS SqlServer中的并发事务管理

Question

I have a question concerning transaction isolation in SQL Server. The default isolation level is set to 2 (READ_COMMITED). In the first transaction, I insert some data in table users; in the second, I try, unsuccessfully, to select all data from the same table, it seems that the second transaction waits for the first one to commit/rollback.

Does anyone have an explanation?

Answer 1

That is exactly what the read committed means, the second transaction will wait until it is able to read all the data. There are ways to either read the uncommitted data or skip it, but that is not something you would normally want to do.

There is quite a lot of material available for this, for example this one in TechNet