From: | Vincenzo Romano <vincenzo(dot)romano(at)notorand(dot)it> |
---|---|
To: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: On Scalability |
Date: | 2010-10-07 12:10:11 |
Message-ID: | AANLkTi==OD9afGEDOm7OY3KYydLXcMj=kO7M5+QFbaM0@mail.gmail.com |
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Lists: | pgsql-hackers pgsql-performance |
2010/10/7 Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>:
> On 07.10.2010 10:41, Simon Riggs wrote:
>>
>> On Thu, 2010-10-07 at 10:28 +0300, Heikki Linnakangas wrote:
>>
>>> constraint exclusion of CHECK constraints on the partitions is
>>> exponential
>>
>> Constraint exclusion is linear with respect to number of partitions.
>> Why do you say exponential?
>
> For some reason I thought the planner needs to check the constraints of the
> partitions against each other, but you're right, clearly that's not the
> case. Linear it is.
>
> --
> Heikki Linnakangas
> EnterpriseDB http://www.enterprisedb.com
>
Making these things sub-linear (whether not O(log n) or even O(1) ),
provided that there's way to, would make this RDBMS more appealing
to enterprises.
I mean also partial indexes (as an alternative to table partitioning).
Being able to effectively cope with "a dozen child tables or so" it's more
like an amateur feature.
If you really need partitioning (or just hierarchical stuff) I think you'll need
for quite more than a dozen items.
If you partition by just weeks, you'll need 50+ a year.
Is there any precise direction to where look into the code for it?
Is there a way to put this into a wish list?
--
Vincenzo Romano at NotOrAnd Information Technologies
Software Hardware Networking Training Support Security
--
NON QVIETIS MARIBVS NAVTA PERITVS
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