Re: Critical performance problems on large databases - Mailing list pgsql-general

Oleg Bartunov wrote:
> The big issue with LIMIT,OFFSET is that it still use all rows
> for sorting. I already suggested to use partial sorting to avoid
> sorting all rows if one selected only first 20 row, for example.
> It's very important for Web applications because web users usually
> read first 1-2 pages. Our experimnets have shown 6 times performance
> win when using partial sorting.

We do have this TODO item:

    * Allow ORDER BY ... LIMIT to select top values without sort or index
      using a sequential scan for highest/lowest values

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