Microsoft® SQL Server 2012 Unleashed
by Ray Rankins, Paul T. Bertucci, Chris Gallelli, Alex T. Silverstein
Transactions and Locking
SQL Server issues and holds on to locks for the duration of a transaction to ensure the isolation and consistency of the modifications. Data modifications that occur within a transaction acquire exclusive locks, which are then held until the completion of the transaction. Shared locks, or read locks, are held for only as long as the statement needs them; usually, a shared lock is released as soon as data has been read from the resource (for example, row, page, table). You can modify the length of time a shared lock is held by using keywords such as HOLDLOCK in a query or setting the REPEATABLE_READ or SERIALIZABLE lock isolation levels. If one of these options is specified, shared locks are held until the completion ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access