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 >
