On Tue, Oct 25, 2011 at 7:36 PM, Gaojinchao <[email protected]> wrote: > So we hope to add a choice about metadata is not time-dependent. Just like > use data can use a number as a timestamp . > If we can do this, the effect for time will be smaller. We don't use the ntp > server, the cluster also can work normal ? > Can I open a file? I will try to make a patch and share my mind. >
I suppose you could set an attribute on a table that says "use always increasing version rather than timestamp". You'd have to then on a per region basis keep note of the most recent version and rather than use system time, do a +1 per edit coming in. I think hfile already records the version of the last edit added to the file. On open of a region, you'd look at all hfiles and figure the highest verison and then set your version machine to start at highest-version +1. It might not be that hard to add. You'd have to check the code but a while back we made it so we indirectly got version by going to an EnvironmentEdge class. You could add your 'always increasing version' as an atomic long or something and then it would be available throughout. St.Ack
