On Fri, Nov 2, 2012 at 2:46 AM, horschi <hors...@gmail.com> wrote: > might I ask why repair cannot simply ignore anything that is older than > gc-grace? (like Aaron proposed) I agree that repair should not process any > tombstones or anything. But in my mind it sounds reasonable to make repair > ignore timed-out data. Because the timestamp is created on the client, there > is no reason to repair these, right?
IIRC, tombstone timestamps are written by the server, at compaction time. Therefore if you have RF=X, you have X different timestamps relative to GCGraceSeconds. I believe there was another thread about two weeks ago in which Sylvain detailed the problems with what you are proposing, when someone else asked approximately the same question. > I even noticed an increase when running two repairs directly after each > other. So even when data was just repaired, there is still data being > transferred. I assume this is due some columns timing out within that > timeframe and the entire row being repaired. Merkle trees are an optimization, what they trade for this optimization is over-repair. (FWIW, I agree that, if possible, this particular case of over-repair would be nice to eliminate.) =Rob -- =Robert Coli AIM>ALK - rc...@palominodb.com YAHOO - rcoli.palominob SKYPE - rcoli_palominodb
