The first to lines of the query alone give a result in ~3 seconds:

       select first(8) ID from TBL_TEST
       where ID not in (select first(2) ID from TBL_TEST order by ID desc)

The result are just 8 entries. Sorting those 3 entries should then take no
time at all, right?
But by adding the last "order by" it just takes forever...

      select first(8) ID from TBL_TEST
      where ID not in (select first(2) ID from TBL_TEST order by ID desc)
      order by ID desc

Any ideas?



On Fri, Jan 24, 2020 at 2:39 PM Dimitry Sibiryakov s...@ibphoenix.com
[firebird-support] <firebird-support@yahoogroups.com> wrote:

> 24.01.2020 14:29, Matthias Winkler spmm...@gmail.com [firebird-support]
> wrote:
> > I see the very same issue with firebird 3.0.4. Any ideas?
>
>    You made nested loop on 18000*18000 records with sorting on each
> itaretion. It cannot
> be fast.
>
>
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>    WBR, SD.
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  • [firebi... Matthias Winkler spmm...@gmail.com [firebird-support]
    • Re... Mark Rotteveel m...@lawinegevaar.nl [firebird-support]
      • ... Matthias Winkler spmm...@gmail.com [firebird-support]
        • ... Gabor Boros mlngl...@bgss.hu [firebird-support]
        • ... Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
          • ... Matthias Winkler spmm...@gmail.com [firebird-support]
            • ... Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
              • ... Matthias Winkler spmm...@gmail.com [firebird-support]
                • ... Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
          • ... Mark Rotteveel m...@lawinegevaar.nl [firebird-support]
            • ... Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
              • ... Karol Bieniaszewski liviusliv...@poczta.onet.pl [firebird-support]
                • ... Matthias Winkler spmm...@gmail.com [firebird-support]
                • ... setysvar setys...@gmail.com [firebird-support]
                • ... Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
                • ... Matthias Winkler spmm...@gmail.com [firebird-support]

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