Re: some problems when i use postgresql 8.4.2 in my projects .

From: Leo Mannhart
Subject: Re: some problems when i use postgresql 8.4.2 in my projects .
Date: ,
Msg-id: 4B69934E.6060606@beecom.ch
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In response to: some problems when i use postgresql 8.4.2 in my projects .  ()
List: pgsql-performance

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some problems when i use postgresql 8.4.2 in my projects .  (, )
 Re: some problems when i use postgresql 8.4.2 in my projects .  (Robert Haas, )
 Re: some problems when i use postgresql 8.4.2 in my projects .  (Leo Mannhart, )
 Re: some problems when i use postgresql 8.4.2 in my projects .  (Pierre Frédéric Caillaud<>, )

 wrote:
> after shaming , I think i should pick out some my points:
>  the unique constraints actualy kill concurrency write transaction when
> concurrency insert violate the unique constraints , they block each
> other , i test this in oracle10g, has the same behavour. I think this
> may be reasonable because the uqniue check must be  the seriazable check .
> for resolve this problem , i do the unique check in application as
> possible , but in big concurrency env , this is not good way .
>

How can you enforce uniqueness in the application? If you implement it
correctly, you need considerably longer than letting it do PostgreSQL.
Even if you use some kind of magic, I could not imagine, how you can
implement a unique constraint in the application and gaurantee
uniqueness while at the same time be faster than the RDBMS.

Leo


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