Hi, I saw there are 2 more interesting parameters – a. tombstone_threshold - A ratio of garbage-collectable tombstones to all contained columns, which if exceeded by the SSTable triggers compaction (with no other SSTables) for the purpose of purging the tombstones. Default value – 0.2
b. unchecked_tombstone_compaction - True enables more aggressive than normal tombstone compactions. A single SSTable tombstone compaction runs without checking the likelihood of success. Cassandra 2.0.9 and later. Could I use these to get what I want? Problem I am encountering is even long after gc_grace_seconds I see no reduction in disk space until I run compaction manually. I was thinking to make tombstone threshold close to 0 and unchecked compaction set to true. Also we are not running nodetool repair on weekly basis as of now. From: Eric Stevens [mailto:migh...@gmail.com] Sent: Monday, January 26, 2015 12:11 PM To: user@cassandra.apache.org Subject: Re: Tombstone gc after gc grace seconds My understanding is consistent with Alain's, there's no way to force a tombstone-only compaction, your only option is major compaction. If you're using size tiered, that comes with its own drawbacks. I wonder if there's a technical limitation that prevents introducing a shadowed data cleanup style operation (overwritten data, including deletes, plus tombstones past their gc grace period); or maybe even couple it directly with cleanup since most of the work (rewriting old SSTables) would be identical. I can't think of something off the top of my head, but it would be so useful that it seems like there's got to be something I'm missing. On Mon, Jan 26, 2015 at 4:15 AM, Alain RODRIGUEZ <arodr...@gmail.com<mailto:arodr...@gmail.com>> wrote: I don't think that such a thing exists as SSTables are immutable. You compact it entirely or you don't. Minor compaction will eventually evict tombstones. If it is too slow, AFAIK, the "better" solution is a major compaction. C*heers, Alain 2015-01-23 0:00 GMT+01:00 Ravi Agrawal <ragra...@clearpoolgroup.com<mailto:ragra...@clearpoolgroup.com>>: Hi, I want to trigger just tombstone compaction after gc grace seconds is completed not nodetool compact keyspace column family. Anyway I can do that? Thanks
