Benefits of an updatable reader?

Question

I was wondering what are the benefits of using an updatable read lock rather than the following steps:

• Use read lock
• Check the condition to see if we need to block the record
• Disable read lock
• Take write lock
• Perform update
• Record Lock

One obvious drawback of performing the above steps, in contrast to setting an updated read lock, is that between steps 3 and 4 there is a time window where another thread can take a write lock.

Beyond this benefit, what other benefits will you find in order to take an updated read lock over the steps above?

Answer 1

-, " ".

, , 3 4 , . , 3 4, , 2.

, , :

• , (, , ). , , . ( ).

• , , 2, , , .

• :

  • , ,
  • Take Write Lock
  • .

• :

  • , .
  • , .
  • ( ).
  • .
  • .
  • .

, 4 , , . , , , .

, , , , . , , , , .

---

, , , ( , ). , , - , .

, , , , - .

, , , .

, , , . , , , , . * , , .

, , , , , , .

* "-" , , , ints ReaderWriterLockSlim, , . , , .

Answer 2

, , , , .