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HBase, mail # user - Maximum number of tables ?


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Re: Maximum number of tables ?
Michael Segel 2012-07-13, 15:42
Currently there is a hardcoded limit on the number of regions that a region server can manage.
Its 1500.
Note that if the number of regions gets to around 1000 regions per region server, you end up with a performance hit. (YMMV)

So if you have 1 region per table, there's a real limit of 1500 tables * number of RS nodes.

Note: You will probably die well before hitting this limit, again YMMV.
On Jul 13, 2012, at 3:14 AM, N Keywal wrote:

> Hi,
>
> There is no real limits as far as I know. As you will have one region
> per table (at least :-), the number of region will be something to
> monitor carefully  if you need thousands of table. See
> http://hbase.apache.org/book.html#arch.regions.size.
>
> Don't forget that you can add as many column as you want, and that an
> empty cell cost nothing. For example, a class hierarchy is often
> mapped to multiple tables in a RDBMS, while in HBase having a single
> table for the same hierarchy makes much more sense. Moreover, there is
> no transaction between tables, so sometimes a 'uml composition' will
> go to a single table. And so on.
>
> N.
>
> On Fri, Jul 13, 2012 at 9:04 AM, Adrien Mogenet
> <[EMAIL PROTECTED]> wrote:
>> Hi there,
>>
>> I read some good practices about number of columns / column families, but
>> nothing about the number of tables.
>> What if I need to spread my data among hundred or thousand (big) tables ?
>> What should I care about ? I guess I should keep a tight number of
>> storeFiles per RegionServer ?
>>
>> --
>> Adrien Mogenet
>> http://www.mogenet.me
>