[CASSANDRA-2494] Quorum reads are not monotonically consistent

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Severity: Low
• Assignee: Jonathan Ellis
• Reporter: Sean Bridges

Authors

Jonathan Ellis

Reviewers

Sylvain Lebresne

• Created: 17/Apr/11 14:29
• Updated: 04/Dec/19 19:38
• Resolved: 11/Aug/11 19:29

Description

As discussed in this thread,

http://www.mail-archive.com/[e-mail]/msg12421.html

Quorum reads should be consistent. Assume we have a cluster of 3 nodes (X,Y,Z) and a replication factor of 3. If a write of N is committed to X, but not Y and Z, then a read from X should not return N unless the read is committed to at least two nodes. To ensure this, a read from X should wait for an ack of the read repair write from either Y or Z before returning.

Are there system tests for cassandra? If so, there should be a test similar to the original post in the email thread. One thread should write 1,2,3... at consistency level ONE. Another thread should read at consistency level QUORUM from a random host, and verify that each read is >= the last read.

Issue Links

• is related to: CASSANDRA-15442 Read repair implicitly increases read timeout value