Also, depending on your version of HBase that you are running you may have to bring down the cluster to merge and not just the table:
https://issues.apache.org/jira/browse/HBASE-1621 On Tue, Jul 17, 2012 at 7:26 PM, Amandeep Khurana <[email protected]> wrote: > You shouldn't have empty regions. Using timestamp will give you > regions that are always half filled except the last one to which you > are writing the current time range. The moment that'll fill up, split > and you'll again be writing to the last region. How did you end up > with empty regions? Did you pre-split? > > On Jul 17, 2012, at 7:15 PM, Michael Segel <[email protected]> > wrote: > > > Find a different row key? > > > > The problem with merging regions is that once you merge the regions, any > net new regions will still have the same problem. So you'll have to merge > again, and again and again. > > You're always filling to the left of the last key. > > > > In order to merge, you have to take the table offline. At least that's > my understanding. So its not a good thing. > > > > > > On Jul 17, 2012, at 11:08 AM, Ionut Ignatescu wrote: > > > >> My usecase: I have several tabels with key starting with a timestamp. > Also, > >> this tabels have set data retention to 30 days. > >> Table size is around 1Tb(3Tb replicated) and data is inserted regular(on > >> 5minute, ~200Mb is inserted). > >> File size is set to 1Gb. I have this tables in use for almost half an > year > >> and now a table has around 6k partitions and 40% of them are empty. > >> The problem: the number of regions per region server is now pretty high. > >> Questions: > >> Which approach is better? > >> - to merge adiacent empty partitions in a bigger one? > >> - to merge empty partitions to non-empty partitions? > >> Also, I'm wondering why regions merge is not part of major compactions > and > >> why it's neccesary to stop the > >> entire fleet to solve this problem. > >> > >> > >> > >> Regards, > >> > >> Ionut I. > >> > >> > >> > > > -- Kevin O'Dell Customer Operations Engineer, Cloudera
