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HBase >> mail # user >> one column family but lots of tables

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RE: one column family but lots of tables
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

From: Koert Kuipers [[EMAIL PROTECTED]]
Sent: Thursday, August 22, 2013 12:30 PM
To: [EMAIL PROTECTED]; 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:

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 <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> 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>

From: Koert Kuipers [[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>]
Sent: Thursday, August 22, 2013 8:06 AM
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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