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From Anil Gupta <anilgupt...@gmail.com>
Subject Re: alter column family - possible operational impacts on big tables
Date Fri, 09 Oct 2015 13:46:24 GMT
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 <nicolae.marasoiu@adswizz.com> 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 <jean-marc@spaggiari.org>
> 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 <nicolae.marasoiu@adswizz.com>:
> 
>> 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
>> 

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