[CASSANDRA-6106] Provide timestamp with true microsecond resolution

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Won't Fix
• Fix Version/s: 2.2.0 beta 1
• Labels: timestamps

Environment

DSE Cassandra 3.1, but also HEAD

• Assignee: Benedict Elliott Smith
• Reporter: Christopher Smith

Authors

Benedict Elliott Smith

• Created: 26/Sep/13 23:25
• Updated: 16/Apr/19 09:32
• Resolved: 05/Feb/15 18:35

Description

I noticed this blog post: http://aphyr.com/posts/294-call-me-maybe-cassandra mentioned issues with millisecond rounding in timestamps and was able to reproduce the issue. If I specify a timestamp in a mutating query, I get microsecond precision, but if I don't, I get timestamps rounded to the nearest millisecond, at least for my first query on a given connection, which substantially increases the possibilities of collision.

I believe I found the offending code, though I am by no means sure this is comprehensive. I think we probably need a fairly comprehensive replacement of all uses of System.currentTimeMillis() with System.nanoTime().

Issue Links

• duplicates: CASSANDRA-7919 Change timestamp representation to timeuuid
• relates to: CASSANDRA-6123 Break timestamp ties consistently for a given user requests