Hi Ivan,
For #1, let's consider regions A, B, C and D all in server S. If you merge A and B togher and C and D togher, still in S, you will have A' and C' regions only on S. Now, if you try to merge again A' and C' into a new bigger region, this will fail silently until A' and C' are major compacted. Indeed, before major compaction, A' and C' will both still contain references to A+B and C+D files/regions. So to be able to merge A' and C' you need this to be cleaned and so you need to major compact them. HTH, JM 2015-07-15 10:43 GMT-04:00 Ted Yu <[email protected]>: > bq. that some times merge just does not work. > > Can you identify under what scenario the merge doesn't work (through closer > inspection of the region server log - assuming you have DEBUG logging > turned on) ? > > bq. Are there minimum requirements for two regions to be merged? > > If the two adjacent regions to be merged are on different servers, HBase > would move one of them to the other region's server. > > bq. If those requirements are not met, does the merge process exit > silently? > > Nothing I am aware of. > > Cheers > > On Wed, Jul 15, 2015 at 3:08 AM, Ivan Brondino <[email protected]> > wrote: > > > Hi, > > > > We are using Hbase 0.98.6 and Hadoop 2.5.0 - cdh 5.3.5. > > > > We have a couple of questions regarding splits and merge: > > > > 1) Since both split and merge are async invocations on the client side, > we > > have a naîve > > workaround to make it synchronous that is to look at the RS Info Server > via > > an HttpClient checking > > for pending tasks to be finished. Once all tasks are finished in all RS > we > > issue the next split/merge for the same table. Is there a better way to > do > > it? > > > > 2) Regarding merges, we've noticed that some times merge just does not > > work. We see on the master log that merge request is issued and it > forwards > > it to the corresponding RS but then on the RS nothing happens. We always > > merge two regions on the same region server. > > Are there minimum requirements for two regions to be merged? If those > > requirements are not met, does the merge process exit silently? > > > > Thanks in advance, > > > > Iván > > >
