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From Nicolae Marasoiu <nicolae.maras...@adswizz.com>
Subject Re: alter column family - possible operational impacts on big tables
Date Fri, 09 Oct 2015 08:15:55 GMT
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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