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Re: More then 1600 columns?

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Dmitriy Igrishin <dmitigr(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: More then 1600 columns?
Date: 2010-11-12 07:59:58
Message-ID: AANLkTi=JqQTSwdtsifFb7RCWmM9DGw38NNTfqXJd2G47@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-general
2010/11/12 Dmitriy Igrishin <dmitigr(at)gmail(dot)com>:
> Hey Peter,
>
> Unfortunately, there is no indexes on arrays (only on expressions).

there are indexes on arrays - you can use a GiST, Gin indexes.

regards

Pavel


> With hstore we can easily create GiST index for effective access.
>
> 2010/11/12 Peter Bex <Peter(dot)Bex(at)xs4all(dot)nl>
>>
>> On Fri, Nov 12, 2010 at 10:17:50AM +0300, Dmitriy Igrishin wrote:
>> > Hey Mark,
>> >
>> > Yeah, I can't imagine an entity in a real project even with more than
>> > 100
>> > columns. Its rare case.
>> > But if you entities (rows/tuples) of some class (table) can contains
>> > variable
>> > set of columns (properties) you can look at hstore contrib module.
>>
>> What can also work extremely well is storing the data in an array.
>> If you need to access the array based on more meaningful keys you could
>> store key/index pairs in another table.
>>
>> This approach only works well if you have multiple arrays with the same
>> layout.  You probably also need to build up your query dynamically if
>> you need to access variable numbers of datapoints.
>>
>> Cheers,
>> Peter
>> --
>> http://sjamaan.ath.cx
>> --
>> "The process of preparing programs for a digital computer
>>  is especially attractive, not only because it can be economically
>>  and scientifically rewarding, but also because it can be an aesthetic
>>  experience much like composing poetry or music."
>>                                                        -- Donald Knuth
>>
>> --
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>
>
>
> --
> // Dmitriy.
>
>
>

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