Pessimistic/ Optimistic concurrency control mechanisms

[calico]

Hi,

How can I know the type of concurrency control that have been set on our Sql Server ?
Pessimistic or Optimiistic ?

I read that MS Sql Server supports a wide range of Pessimistic and Optimistic concurrency control mechanisms. Can you enumerate that are they ?

Thank you !

Danny Danny Presse

 

[foxdev]

Pessimistic is SQL Server's default. For a more complete explanation, see the BOL topic "cursors, concurrency".
Robert Bradley

http://www.foxdev.com/

http://www.agrainofhope.org

 

[TomSark]

Acutally, the transaction isolation level defines the degree of pessistic behavior that SQL Server imposes on locking behavior.

The default isolation level is READ COMMITTED, where locks (Shared & Exclusive) are honored, but things like phantom reads and non-repeatable reads can occur with this level.

As you increase the isolation level, these weird read problems go away, but locks are held longer. Check out books-online for more info...

Tom Davis
tdavis@sark.com

http://www.sarkdallas.com