Thanks Jeff for your feedback! > I’d strongly suspect the people seeing this have corruption from missing checksums and latent bitflips.
I agree. Even if that's the case, negative timestamp deletions looks like are not supported in 5.0 if the analysis is right. Should we reject negative timestamp deletions in 5.0 or change the sstable format mid-release to support this use case ? Cheers, Paulo On Tue, 6 Oct 2026 at 23:48 Jeff Jirsa <[email protected]> wrote: > There was a time probably a 17 years ago where I used specially crafted > timestamps to implement a read-free leaderboard concept for a high > throughput video game system that didn’t care about the lossy nature of > score conflicts, so I’m sure some people do horrible things with client > supplied timestamps to trick cell resolution (because I was one of those > people), but even I didn’t think this went to the markedForDeleteAt value > on deletions. > > I’d strongly suspect the people seeing this have corruption from missing > checksums and latent bitflips. > > On Oct 6, 2026, at 8:40 PM, Paulo Motta <[email protected]> wrote: > > > Hi, > > According to this AI-assisted analysis on CASSANDRA-21729[1], negative > deletion timestamps which are accepted by CQL will > cause CorruptSSTableException on 5.0 but not on 4.0. This is easily > reproducible on 5.0 with: > INSERT INTO ks.t (k, v) VALUES (1, 1) USING TIMESTAMP 100; > DELETE FROM ks.t USING TIMESTAMP -5 WHERE k = 1; > SELECT * FROM ks.t WHERE k = 1; -- after flush, throws > CorruptSSTableException (works fine in 4.0) > > I can't think of a legitimate reason why someone would use negative > timestamps other than a bug/corruption, but it turns out that some 4.X > users are reporting seeing this error after upgrading in both BTI and BIG > formats. My guess is this surfacing some old corruption not detected by 4.X. > > Can someone with more expertise in the area confirm the bug is legitimate ? > > The fix might involve an sstable format change, or stop supporting > negative timestamps. I would personally prefer to stop supporting negative > timestamps, and a flag to disable this for obscure use cases. > > Let me know what do you think, > > Paulo > > [1] - > https://issues.apache.org/jira/browse/CASSANDRA-21729?focusedCommentId=18124156&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-18124156 > >
