Re: Critical performance problems on large databases

Bruce Momjian wrote:
>
> 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

It may not be wise to disregard the index if there is one for the ORDER
BY.

JLL

>
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>   Bruce Momjian                        |  http://candle.pha.pa.us
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