As one of the committers to cassandra.gem, microseconds is the way to go. Specificity is nice to have when you haven't been thinking about timestamps and suddenly have a deep, abiding need to care about them.
I cannot understate that. It is much easier to remove the specificity than it is to put it in after the fact. -- Jeff On Thu, Mar 18, 2010 at 12:36 AM, Jonathan Hseu <vom...@vomjom.net> wrote: > Jonathan Ellis suggested that I bring this issue to the dev mailing list: > > Cassandra should recommended a default timestamp across all clients > libraries. > > Many users on IRC are having difficulty when using different clients because > different clients are using different timestamps. If you insert with one > client, you may not be able to modify the key later with another. The > Cassandra website doesn't seem to mention timestamps much, so users get > confused when operations fail on certain clients. > > Here's what different clients are using: > > 1. Cassandra CLI: Milliseconds since UTC epoch. > 2. lazyboy: Seconds since UTC epoch. It used to be seconds since local time > epoch. Now it's changing again to microseconds since UTC epoch. > 3. driftx's client: Milliseconds since UTC epoch. > 4. The example app, Twissandra: Microseconds since UTC epoch. > 5. pycassa: Microseconds since UTC epoch. It used to be seconds since local > time epoch. > 6. The most popular Cassandra Ruby client: Microseconds since UTC epoch. > > Here's why the default recommended timestamp should be microseconds since > UTC epoch: > > 1. It allows backwards-compatibility. Some people are already using > microseconds, so if it suddenly switched to milliseconds, all the timestamps > would be smaller, and they'd be unable to insert or remove existing columns. > Microsecond timestamps would always be greater than millisecond timestamps, > so new operations would work. > 2. There exist reasons people would want to use microseconds over > milliseconds (finer granularity), but I don't think there are any reasons > one would prefer milliseconds over microseconds. > > 3 (just for me). I just changed pycassa to microseconds, and I'd hate to > change it again :( > > > Jonathan Hseu >
