Re: enable_incremental_sort changes query behavior

On Wed, 30 Sep 2020 at 21:21, James Coleman <jtc331@gmail.com> wrote:
>
> On Sat, Sep 26, 2020 at 2:49 PM Jaime Casanova
> <jaime.casanova@2ndquadrant.com> wrote:
> >
> > Hi,
> >
> > With sqlsmith I found a query that gives this error:
> > ERROR:  ORDER/GROUP BY expression not found in targetlist
> >
[...]
> >
> > But if I set enable_incremental_sort to off the query gets executed
> > without problems (attached the explain produced for that case)
>
> Thanks for the report.
>

Hi,

by experiment I reduced the query to this

--- 0 ---
select distinct
        subq_0.c1 as c0,
        case when (true = pg_catalog.pg_rotate_logfile_old()) then
                ref_0.t else ref_0.t
        end
             as c4
        from
          public.ref_0,
          lateral (select

                ref_0.i as c1
              from
                generate_series(1, 100) as ref_1) as subq_0
--- 0 ---

the only custom table already needed can be created with this commands:

--- 0 ---
create table ref_0 as select repeat('abcde', (random() * 10)::integer)
t, random() * 1000 i from generate_series(1, 500000);
create index on ref_0 (i);
analyze ref_0 ;
--- 0 ---


> Is there by an chance an index on ref_0.radi_text_temp?
>

there is an index involved but not on that field, commands above
create the index in the right column... after that, ANALYZE the table

> And if you set enable_hashagg = off what plan do you get (or error)?
>

same error

-- 
Jaime Casanova                      www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services