Thread: BUG #5768: Inefficiency of large offsets should be mentioned on SELECT documentation page

The following bug has been logged online:

Bug reference:      5768
Logged by:          Pavel Arnost
Email address:      pavel.arnost@loutka.cz
PostgreSQL version: 9.01
Operating system:   N/A
Description:        Inefficiency of large offsets should be mentioned on
SELECT documentation page
Details:

Inefficiency of large offsets should be mentioned on SELECT documentation
page - now it's only on "LIMIT and OFFSET" page.

Pavel Arnost wrote:
>
> The following bug has been logged online:
>
> Bug reference:      5768
> Logged by:          Pavel Arnost
> Email address:      pavel.arnost@loutka.cz
> PostgreSQL version: 9.01
> Operating system:   N/A
> Description:        Inefficiency of large offsets should be mentioned on
> SELECT documentation page
> Details:
>
> Inefficiency of large offsets should be mentioned on SELECT documentation
> page - now it's only on "LIMIT and OFFSET" page.

I have no idea what you are suggesting.  There is no LIMIT and OFFSET
page in the manuals.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

Hi Bruce,

On 30/11/10 03:11, Bruce Momjian wrote:
> Pavel Arnost wrote:
>> The following bug has been logged online:
>>
>> Bug reference:      5768
>> Logged by:          Pavel Arnost
>> Email address:      pavel.arnost@loutka.cz
>> PostgreSQL version: 9.01
>> Operating system:   N/A
>> Description:        Inefficiency of large offsets should be mentioned on
>> SELECT documentation page
>> Details:
>>
>> Inefficiency of large offsets should be mentioned on SELECT documentation
>> page - now it's only on "LIMIT and OFFSET" page.
> I have no idea what you are suggesting.  There is no LIMIT and OFFSET
> page in the manuals
Section 7.6, "LIMIT and OFFSET":
http://www.postgresql.org/docs/current/static/queries-limit.html

Perhaps a link from the SELECT page to this link would be sufficient.

Tom

Hi,

by "LIMIT and OFFSET" page I meant
http://www.postgresql.org/docs/9/static/queries-limit.html, it has "LIMIT
and OFFSET" heading. At the end of the page, there is this sentence:

"The rows skipped by an OFFSET clause still have to be computed inside the
server; therefore a large OFFSET might be inefficient."

This sentence should also appear on the SELECT page
(http://www.postgresql.org/docs/9/static/sql-select.html). Maybe it could
also more clearly state that paging with LIMIT and OFFSET over large data
set is slow and that user should use WHERE > and LIMIT instead of OFFSET and
LIMIT.

Regards,
Pavel Arnost

--------------------------------------------------
From: "Bruce Momjian" <bruce@momjian.us>
Sent: Tuesday, November 30, 2010 4:11 AM
To: "Pavel Arnost" <pavel.arnost@loutka.cz>
Cc: <pgsql-bugs@postgresql.org>
Subject: Re: [BUGS] BUG #5768: Inefficiency of large offsets should be
mentioned on SELECT documentation page

> Pavel Arnost wrote:
>>
>> The following bug has been logged online:
>>
>> Bug reference:      5768
>> Logged by:          Pavel Arnost
>> Email address:      pavel.arnost@loutka.cz
>> PostgreSQL version: 9.01
>> Operating system:   N/A
>> Description:        Inefficiency of large offsets should be mentioned on
>> SELECT documentation page
>> Details:
>>
>> Inefficiency of large offsets should be mentioned on SELECT documentation
>> page - now it's only on "LIMIT and OFFSET" page.
>
> I have no idea what you are suggesting.  There is no LIMIT and OFFSET
> page in the manuals.
>
> --
>  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
>  EnterpriseDB                             http://enterprisedb.com
>
>  + It's impossible for everything to be true. +
>