From: Andras Kutrovics <n-drew@freemail.hu>
To: pgsql-sql@postgresql.org
Subject: Re: Simple SQL Question
Date: Tue, 09 Nov 2004 10:16:22 +0100
Message-ID: <41908AE6.80202@freemail.hu> (raw)
In-Reply-To: <1099678157.39887.15.camel@taz.oficina>
References: <418BB051.6070808@freemail.hu>
<1099678157.39887.15.camel@taz.oficina>
Franco Bruno Borghesi wrote:
Hi!
Sorry for being late with the answer, I was busy at one of our customer;)
> wouldn't it be easier using offset & limit?: you always select from the
> table with an itemkey,location order by clause. You save the current
> offset between requests, and for every request you re-execute the query
> with a different offset.
Sure, but sometimes I have to query by name, and dont want to create
another query component.
> If you still want to go with what you already have, you should keep the
> lastItemKey and lastLocaltion values between requests, and your where
> clause should be something like:
> WHERE (itemKey=:lastItemKey AND location>:lastLocation) OR
> (itemKey>:lastItemKey)
It works perfectly, but I have to consider the performance issue,
because if i use 'or' statement, postgres doesn't use index scan,
and I also have tables with 3 or more keys and 500.000 records ,
where
the performance of this method is poor.
Maybe I will end up using limit and offset in case of incremental
fetching,but if the table is modified between requests, it can behave
weird.
Is there a perfect solution to this?
Sorry for the english
Thank you again,
Andras Kutrovics
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Subject: Re: Simple SQL Question
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