http://www.datastax.com/dev/blog/preparing-for-the-leap-second gives a pretty good overview
If you are using a timestamp as part of your primary key, this is the situation where you could end up overwriting data. I would suggest using timeuuid instead which will ensure that you get different primary keys even for data inserted at the exact same timestamp. The blog post also suggests using certain monotonic timestamp classes in Java however these will not help you if you have multiple clients that may overwrite data. As for the interleaving or out of order problem, this is hard to address in Cassandra without resorting to external coordination or LWTs. If you are relying on a wall clock to guarantee order in a distributed system you will get yourself into trouble even without leap seconds (clock drift, NTP inaccuracy etc). On Thu, 20 Oct 2016 at 10:30 Anuj Wadehra <anujw_2...@yahoo.co.in> wrote: > Hi, > > I would like to know how you guys handle leap seconds with Cassandra. > > I am not bothered about the livelock issue as we are using appropriate > versions of Linux and Java. I am more interested in finding an optimum > answer for the following question: > > How do you handle wrong ordering of multiple writes (on same row and > column) during the leap second? You may overwrite the new value with old > one (disaster). > > And Downtime is no option :) > > I can see that CASSANDRA-9131 is still open.. > > FYI..we are on 2.0.14 .. > > > Thanks > Anuj > -- Ben Bromhead CTO | Instaclustr <https://www.instaclustr.com/> +1 650 284 9692 Managed Cassandra / Spark on AWS, Azure and Softlayer
