Hi Robert,
Any comments or suggestions ? Thanks Anuj Wadehra Sent from Yahoo Mail on Android From:"Anuj Wadehra" <anujw_2...@yahoo.co.in> Date:Wed, 15 Apr, 2015 at 8:59 am Subject:Re: Drawbacks of Major Compaction now that Automatic Tombstone Compaction Exists Hi Robert, By automatic tombstone compaction, I am referring to tombstone_threshold sub property under compaction strategy in CQL. It is 0.2 by default. So what I understand from the Datastax documentation is that even if a sstable does not find sstables of similar size (STCS) , an automatic tombstone compaction will trigger on sstable when 20% data is tombstone. This compaction works on single sstable only. How Major compaction is related to automatic tombstone compaction? Earlier we used to say that Major compaction is not recommended because one huge sstable formed after Major compaction will not find any similar size sstables unless huge data is written in new sstables and thus tombstones will be there in the huge sstable unnnecessarily for long time. My understanding is that automatic tombstone compaction will allow tombstone collection on huge sstable formed after major compaction and that should no more be considered a drawback. Please confirm my understanding. Also I want to know are there any other side effects and inefficiences of say 100+ gb sstable? Please refer to my fist email on the issue. We tried splitting sstable using sstablesplit but just because all small sstables are generated of same size, STCS compacted them back to single giant sstable as soon as we started Cassandra. Any other alternatives ? JIRA for the Issue of numerous tiny sstables being generated after repair is still open and we want a confirmation that if we face such issue in prod we can go ahead with one time major compaction. Thanks Anuj Wadehra From:"Robert Coli" <rc...@eventbrite.com> Date:Tue, 14 Apr, 2015 at 12:54 am Subject:Re: Drawbacks of Major Compaction now that Automatic Tombstone Compaction Exists On Mon, Apr 13, 2015 at 10:52 AM, Anuj Wadehra <anujw_2...@yahoo.co.in> wrote: Any comments on side effects of Major compaction especially when sstable generated is 100+ GB? I have no idea how this interacts with the automatic compaction stuff; if you find out, let us know? But if you want to do a major and don't want to deal with One Big SSTable afterwards, stop the node and then run sstable_split utility. =Rob
