From: Arnau <arnaulist@andromeiberica.com>
To: PostgreSQL Performance <pgsql-performance@postgresql.org>
Subject: Re: How PostgreSQL handles multiple DDBB instances?
Date: Fri, 25 May 2007 19:16:05 +0200
Message-ID: <465719D5.9040107@andromeiberica.com> (raw)
In-Reply-To: <8684.1180103080@sss.pgh.pa.us>
References: <4656A3BE.1070409@andromeiberica.com>
<8684.1180103080@sss.pgh.pa.us>
Hi Tom,
> Arnau <arnaulist@andromeiberica.com> writes:
>> I have an application that works with multiple customers. Thinking in
>> scalability we are thinking in applying the following approaches:
>
>> - Create a separate database instance for each customer.
>> - We think that customer's DB will be quite small, about 200MB as
>> average.
>> - The number of clients, then DDBB, can be significant(thousands).
>> - Have as many customers as possible on the same server, so a single
>> server could have more than 300 DDBB instances.
>
> This is probably a bad idea, unless each customer's performance demands
> are so low that you can afford to use very small shared-memory settings
> for each instance. But even small settings will probably eat ~10MB per
> instance --- can you afford to build these machines with multiple GB of
> RAM?
>
> Can you instead run things with one postmaster per machine and one
> database per customer within that instance? From a performance
> perspective this is likely to work much better.
What I meant is just have only one postmaster per server and a lot of
databases running in it. Something like that:
template1=# \l
List of databases
Name | Owner | Encoding
-------------------+-----------+----------
alertwdv2 | gguridi | LATIN1
postgres | postgres | LATIN1
template0 | postgres | LATIN1
template1 | postgres | LATIN1
voicexml | root | LATIN1
wikidb | root | LATIN1
(6 rows)
Here I just have 6 databases, so my doubt is if instead having 6
databases have 300/600 bases running on the same postmaster how this
will impact the performance e.g.
template1=# \l
List of databases
Name | Owner | Encoding
-------------------+-----------+----------
template0 | postgres | LATIN1
template1 | postgres | LATIN1
customers_group_1 | root | LATIN1
(3 rows)
Instead of:
template1=# \l
List of databases
Name | Owner | Encoding
-------------------+-----------+----------
template0 | postgres | LATIN1
template1 | postgres | LATIN1
customers_1 | root | LATIN1
customers_2 | root | LATIN1
customers_3 | root | LATIN1
...
customers_500 | root | LATIN1
(502 rows)
> If you desire to give the customers database-superuser capability then
> this probably won't do, but if they are restricted users it might be OK.
The users won't have superuser access just execute plain queries.
Thank you very much
--
Arnau
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To: pgsql-performance@postgresql.org
Cc: arnaulist@andromeiberica.com
Subject: Re: How PostgreSQL handles multiple DDBB instances?
In-Reply-To: <465719D5.9040107@andromeiberica.com>
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