Re: Can this query go faster???

From: Tino Wildenhain <tino(at)wildenhain(dot)de>
To: Joost Kraaijeveld <J(dot)Kraaijeveld(at)Askesis(dot)nl>
Cc: Csaba Nagy <nagy(at)ecircle-ag(dot)com>, Pgsql-Performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Can this query go faster???
Date: 2005-12-06 12:30:25
Message-ID: 43958461.2060106@wildenhain.de
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

Joost Kraaijeveld schrieb:
> On Tue, 2005-12-06 at 12:36 +0100, Tino Wildenhain wrote:
>
>>>I just tried it: a cursor is not faster (what does not surprise me at
>>>all, as the amount of work looks the same to me)
>>
>>Actually no, if you scroll forward, you just ask the database for the
>>next rows to materialize. So if you are ahead in your database and
>>ask for next rows, it should be faster then working w/ an offset
>>from start each time.
>
> Ah, a misunderstanding: I only need to calculate an index if the user
> wants a record that is not in or adjacent to the cache (in which case I
> can do a "select values > last value in the cache". So I must always
> materialize all rows below the wanted index.
>
Yes, but still advancing a few blocks from where the cursor is
should be faster then re-issuing the query and scroll thru
the whole resultset to where you want to go.

In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Csaba Nagy 2005-12-06 12:32:57 Re: Can this query go faster???
Previous Message Joost Kraaijeveld 2005-12-06 12:20:45 Re: Can this query go faster???