Thanks, JM It seems like the sole difference btwn major and minor compaction is the number of files (to be all or just a subset of storefiles). It mentioned very briefly in http://hbase.apache.org/book<http://hbase.apache.org/book/regions.arch.html>that "Sometimes a minor compaction will ... promote itself to being a major compaction". What does "sometime" exactly mean here? or any policy in HBase that allow application to specify when to promote a minor compaction to be a major (like user or some monitoring service can specify now is offpeak time?) Yun
On Sat, Jun 22, 2013 at 8:51 AM, Jean-Marc Spaggiari < jean-m...@spaggiari.org> wrote: > Hi Yun, > > Few links: > - http://blog.cloudera.com/blog/2012/06/hbase-io-hfile-input-output/ > => There is a small paragraph about compactions which explain when > they are triggered. > - http://hbase.apache.org/book/regions.arch.html 9.7.6.5 > > You are almost right. Only thing is that HBase doesn't know when is > your offpeak, so a major compaction can be triggered anytime if the > minor is promoted to be a major one. > > JM > > 2013/6/22 yun peng <pengyunm...@gmail.com>: > > Hi, All > > > > I am asking the different practices of major and minor compaction... My > > current understanding is that minor compaction, triggered automatically, > > usually run along with online query serving (but in background), so that > it > > is important to make it as lightweight as possible... to minimise > downtime > > (pause time) of online query. > > > > In contrast, the major compaction is invoked in offpeak time and usually > > can be assume to have resource exclusively. It may have a different > > performance optimization goal... > > > > Correct me if wrong, but let me know if HBase does design different > > compaction mechanism this way..? > > > > Regards, > > Yun >
