Correct, a tombstone will only be removed after gc_grace period has elapsed. The default value is set to 10 days which allows a great deal of time for consistency to be achieved prior to deletion. If you are operationally confident that you can achieve consistency via anti-entropy repairs within a shorter period you can always reduce that 10 day interval.
Mark On Fri, Apr 11, 2014 at 3:16 PM, William Oberman <ober...@civicscience.com>wrote: > I'm seeing a lot of articles about a dependency between removing > tombstones and GCGraceSeconds, which might be my problem (I just checked, > and this CF has GCGraceSeconds of 10 days). > > > On Fri, Apr 11, 2014 at 10:10 AM, tommaso barbugli <tbarbu...@gmail.com>wrote: > >> compaction should take care of it; for me it never worked so I run >> nodetool compaction on every node; that does it. >> >> >> 2014-04-11 16:05 GMT+02:00 William Oberman <ober...@civicscience.com>: >> >> I'm wondering what will clear tombstoned rows? nodetool cleanup, >>> nodetool repair, or time (as in just wait)? >>> >>> I had a CF that was more or less storing session information. After >>> some time, we decided that one piece of this information was pointless to >>> track (and was 90%+ of the columns, and in 99% of those cases was ALL >>> columns for a row). I wrote a process to remove all of those columns >>> (which again in a vast majority of cases had the effect of removing the >>> whole row). >>> >>> This CF had ~1 billion rows, so I expect to be left with ~100m rows. >>> After I did this mass delete, everything was the same size on disk (which >>> I expected, knowing how tombstoning works). It wasn't 100% clear to me >>> what to poke to cause compactions to clear the tombstones. First I tried >>> nodetool cleanup on a candidate node. But, afterwards the disk usage was >>> the same. Then I tried nodetool repair on that same node. But again, disk >>> usage is still the same. The CF has no snapshots. >>> >>> So, am I misunderstanding something? Is there another operation to try? >>> Do I have to "just wait"? I've only done cleanup/repair on one node. Do >>> I have to run one or the other over all nodes to clear tombstones? >>> >>> Cassandra 1.2.15 if it matters, >>> >>> Thanks! >>> >>> will >>> >> >> > > >
