SQL – With NoLock Hint

When running a query against a database that is highly available and records can be accessed at any time, I typically use the “with (NoLock)” hint in my SQL statements.

This ensures that if I’m accessing the same record as another user that we do not cause a deadlock. NoLock also runs slightly faster because it doesn’t have to acquire a lock on records.

However, note that when using NoLock that you will also be able to see transactions/ records that have not been completed yet/ committed.

Therefore, I don’t recommend using “with (NoLock)” in applications because you could end up getting uncommitted records. I do recommend using “with nolock” when you are just querying the database to check specific records in the table(s) to prevent accidently locking a record someone else/ another application is attempting to access.

Example:

SELECT [Columns]
FROM [Table] with (nolock)
WHERE [condition]


Posted

in

by

Tags:

Comments

Leave a Reply

Your email address will not be published. Required fields are marked *