O'Reilly logo

Hands-On High Performance with Spring 5 by Dinesh Radadiya, Prashant Goswami, Pritesh Shah, Subhash Shah, Chintan Mehta

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Read uncommitted

Read uncommitted is the lowest isolation level. This isolation level defines that a transaction may read data that is still uncommitted by other transactions, which means that the data is not consistent with other parts of the table or the query. This isolation level ensures the quickest performance because data is read from a table block directly, and there is no need for further processing, validation, or other verification; but it may lead to some issues, such as dirty reads.

Let's see the following diagram:

In the preceding diagram, Transaction A writes data; meanwhile, Transaction B reads that same data before Transaction ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required