[CASSANDRA-8287] Row Level Isolation is violated by read repair

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Later
• Severity: Low
• Assignee: Unassigned
• Reporter: Sankalp Kohli
• Created: 11/Nov/14 00:53
• Updated: 03/Jun/21 22:24
• Resolved: 11/Nov/15 17:23

Description

In 1.1, row level isolation was added. As per the blog post
http://www.datastax.com/dev/blog/row-level-isolation

"Cassandra guarantees that the changes to login and password are either both applied or none are."

This is not true with background read repair. Consider this as given in the blog post.
You run
UPDATE Users
SET login='eric22' AND password='f3g$dq!'
WHERE key='550e8400-e29b-41d4-a716-446655440000'
There are 3 machines A,B and C and replication is RF=3
1) Machine A did not get this update as it was down and past hint window.
2) Machine A comes online.
3) You now only read the password.
4) password is now read repaired on A.

SO on machine A, password = f3g$dq! and login is still old

Issue Links

• is related to: CASSANDRA-16710 Read repairs can break row isolation