Message-ID: <4D720975.8050206@optrak.co.uk>
Date: Sat, 05 Mar 2011 09:59:17 +0000
From: Mark Thornton <mthornton@optrak.co.uk>
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To: pgsql-performance@postgresql.org
Subject: Re: Table partitioning
References: <AANLkTin7ZbOU+Z=bCjTbCUsUC=pYq-A2yM5=15gyRgZN@mail.gmail.com>
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On 05/03/2011 09:37, Tobias Brox wrote:
> Sorry for not responding directly to your question and for changing
> the subject ... ;-)
>
> On 4 March 2011 18:18, Landreville<landreville@deadtreepages.com>  wrote:
>> That is partitioned into about 3000 tables by the switchport_id (FK to
>> a lookup table), each table has about 30 000 rows currently (a row is
>> inserted every 5 minutes into each table).
> Does such partitioning really make sense?  My impression is that the
> biggest benefit with table partitioning is to keep old "inactive" data
> out of the caches.  If so, then it doesn't seem to make much sense to
> split a table into 3000 active partitions ... unless, maybe, almost
> all queries goes towards a specific partitioning.
If your partitions a loosely time based and you don't want to discard 
old data, then surely the number of partitions will grow without limit. 
You could have partitions for say the last 12 months plus a single 
partition for 'ancient history', but then you have to transfer the 
content of the oldest month to ancient each month and change the 
constraint on 'ancient'.

Mark