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Date: Wed, 24 Jul 2013 13:58:05 -0400
From: Elliot <yields.falsehood@gmail.com>
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To: Bruce Momjian <bruce@momjian.us>
CC: Anand Muthukrishnan <lucky.developer@gmail.com>,
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Subject: Re: Postgres schema having > 20,000 schemas
References: <D3DD6C1B-5A7B-4432-92D4-690BCB0E6765@gmail.com>
 <20130724142155.GD31462@momjian.us>
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Also, the "Billion Tables Project" mentions a few attempts at databases 
with many tables (20k schemas at 50 tables per schema is one million 
tables). The presentation page is here 
http://www.pgcon.org/2013/schedule/events/595.en.html

On 2013-07-24 10:21, Bruce Momjian wrote:
> On Wed, Jul 24, 2013 at 04:41:07PM +0530, Anand Muthukrishnan wrote:
>> Can a single Postgres database contain more than 20,000 schemas? What are the
>> implications of such a database design.
>>
>> I was reading about postgres schemas here - http://www.postgresql.org/docs/8.2/
>> static/ddl-schemas.html and I'm planning to create one schema per account in my
>> multi-tenant Ruby on Rails app. Each schema would have a set of tables to store
>> data of the relevant account.
>>
>> Each user/schema for all the features we offer, could have 50-60 tables.
>>
>> Can postgres handle all of this without any hiccups, provided I allocate a
>> large EC2 instance to host the database server ?
>>
>> By experience if any one faced trouble with such number of schemas in postgres,
>> they could share and i thought i can get more guidance to avoid such pitfalls.
> Well, I think the big question is whether you want them all in the same
> database (in separate schemas), or in their own databases.  You might
> want to look at this:
>
> 	http://momjian.us/main/blogs/pgblog/2012.html#April_23_2012
>
> We have done some work in improving performance for databases with many
> table and many schemas.  Not sure about the 20k schema performance,
> though.  You might need to just test it.
>



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