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From Koert Kuipers <ko...@tresata.com>
Subject Re: one column family but lots of tables
Date Thu, 22 Aug 2013 22:43:56 GMT
thanks thats helpful


On Thu, Aug 22, 2013 at 5:16 PM, Vladimir Rodionov
<vrodionov@carrieriq.com>wrote:

> Yes, number of tables must be reasonable as well. Region Servers operates
> on 'regions' .
> Each Table can have multiple CFs, each CF can have multiple regions. The
> more regions you have per Region Server -
> the more data you will need to keep in memory, the more time it will take
> to recover  from Region Server failure, therefore
> there is a practical limit on number of regions per one Region Server
> (hundreds - not thousands). It is recommended
> to keep the number of regions per server much less than 1000 (say , 100-
> 500 max).
>
>
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com
> e-mail: vrodionov@carrieriq.com
>
> ________________________________________
> From: Koert Kuipers [koert@tresata.com]
> Sent: Thursday, August 22, 2013 12:30 PM
> To: user@hbase.apache.org; Vladimir Rodionov
> Subject: Re: one column family but lots of tables
>
> if that is the case, how come people keep warning about limiting the
> number of column families to only a handful (with more hbase performance
> will degrade supposedly), yet there seems to be no similar warnings for
> number of tables? see for example here:
> http://comments.gmane.org/gmane.comp.java.hadoop.hbase.user/27616
>
> if a table means at least one column family then the number of tables
> should also be kept to a minumum, no?
>
>
>
>
> On Thu, Aug 22, 2013 at 1:58 PM, Vladimir Rodionov <
> vrodionov@carrieriq.com<mailto:vrodionov@carrieriq.com>> wrote:
> Nope. Column family is per table (its sub-directory inside your table
> directory in HDFS).
> If you have N tables you will always have , at least, N distinct CFs (even
> if they have the same name).
>
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com<http://www.carrieriq.com>
> e-mail: vrodionov@carrieriq.com<mailto:vrodionov@carrieriq.com>
>
> ________________________________________
> From: Koert Kuipers [koert@tresata.com<mailto:koert@tresata.com>]
> Sent: Thursday, August 22, 2013 8:06 AM
> To: user@hbase.apache.org<mailto:user@hbase.apache.org>
> Subject: one column family but lots of tables
>
> i read in multiple places that i should try to limit the number of column
> families in hbase.
>
> do i understand it correctly that when i create lots of tables, but they
> all use the same column family (by name), that i am just using one column
> family and i am OK with respect to limiting number of column families ?
>
> thanks! koert
>
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