On Thu, Jan 14, 2010 at 6:46 AM, August Zajonc <augu...@augustz.com> wrote: > I personally like this last option of expiring entire sstables. It seems > significantly more efficient then scrubbing data. The granularity might be a > bit high, but by columnfamily seems a reasonable trade-off in the short run > for an easier solution. > > For apps that don't want to see the old data, during a read if the data had > a timestamp older than the expire time on the ColumnFamily it could also be > ignored, then when all in an sstable < x, truncate. > > Logs are a great example of this.
I personally think that truncate and a potential TTL are two different things, since as you said, they have very different granularity. In particular, using truncate basically means that all the data in the CF you truncate have exactly the same TTL. Plus, you have to know if a data have a TTL (and which one if you want different CF that you truncate at different time) when you request it. I, for one, have many use where it's not really a desirable solution. Plus, truncate suppose that you deactivate compaction for you CF, which may or may not be affordable. But sure, for some models, and logs are a great example indeed, truncate will be the perfect solution. Anyway, I'm starting to seriously consider giving this TTL idea a shot. We'll see how that goes. -- Sylvain
