Read Committed Snapshot Isolation

PeopleSoft applications use a "pessimistic" implementation of the READ COMMITTED isolation level. SQL Server supports optimistic concurrency control with its implementation of the READ COMMITTED isolation level, called READ COMMITTED SNAPSHOT.

Optimistic concurrency control has these benefits:

  • The overhead required for managing locks is minimized.

  • Data modification operations cannot be blocked by read operations.

Disabling Read Committed Snapshot Isolation

Under normal circumstances, this feature should always remain enabled. You can disable it if a critical problem is identified.

Before disabling the feature:

  • Make sure there are no open transactions. This means that you must close down the application server and the process scheduler.

  • If there is a risk that users are still connected with open transactions, then change the database to single user mode before continuing.

The command to disable the feature is:

ALTER DATABASE dbname
     SET READ_COMMITTED_SNAPSHOT  OFF

The command to change the database to single user mode is:

ALTER DATABASE dbname
     SET SINGLE_USER  ON

See the product documentation for Microsoft SQL Server.