we should put in a test for that. it is certainly a plausible
scenario. in theory it will just flow into the next epoch and everything
will be fine, but we should try it and see.
ben
On 10/19/2010 11:33 AM, Sandy Pratt wrote:
> Just as a thought experiment, I was pondering the following:
>
> ZK stamps each change to its managed state with a zxid (http://hadoop.apache.org/zookeeper/docs/r3.2.1/zookeeperInternals.html).
That ID consists of a 64 bit number in which the upper 32 bits are the epoch, which changes
when the leader does, and the bottom 32 bits are a counter, which is incremented by the leader
with every change. If 1000 changes are made to ZK state each second (which is 1/20th of the
peak rate advertised), then the counter portion will roll over in 2^32 / (86400 * 1000) =
49 days.
>
> Now, assuming that my math is correct, is this an actual concern? For example, if I'm
using ZK to provide locking for a key value store that handles transactions at about that
rate, am I setting myself up for failure?
>
> Thanks,
>
> Sandy
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