Hi Nicolas, For a table with 5k regions, it should not take more than 10 min for alter table operations. Also, in HBase 1.0+, alter table operations does not require disabling the table. So, you are encouraged to upgrade.
Sent from my iPhone > On Oct 9, 2015, at 1:15 AM, Nicolae Marasoiu <[email protected]> > wrote: > > Hi, > > Indeed, we have tables with 1-5000 regions, distributed on 10-15 RSs. > > A few hours are sufficient to do the alter one a single such table, right? > > Thanks, > Nicu > > ________________________________________ > From: Jean-Marc Spaggiari <[email protected]> > Sent: Thursday, October 8, 2015 10:19 PM > To: user > Subject: Re: alter column family - possible operational impacts on big tables > > Hi Nicu, > > Indeed, with 0.94 you have to disable the table before doing the alter. > However, for 30 regions, it should be pretty fast. When you say 30+, are > you talking about like 1K regions? Or more like 32? The alter will only > update the meta table, so not that much impact on the servers. And no > compactions required for that. The ttl will only take effect at the next > compaction by, as you said, filtering out more records. > > JM > > 2015-10-08 10:49 GMT-04:00 Nicolae Marasoiu <[email protected]>: > >> Hi, >> >> >> If we run at night an alter column family, set ttl, my understanding is >> that it will disable the table, make the alter, and re-enable the table, >> which can be some time for large tables with 30+ regions (hbase version >> 0.94 [image: ☹] ). >> >> >> Do you have any advice about this? How long can it take per region? What >> is the operational hit at the time of the alter command being issued, and >> what when compaction runs on the table? I imagine that compaction is not >> too affected by this, just by filtering out more records when re-writing >> the new HFiles, is this correct? >> >> >> Thanks, >> >> Nicu >>
