----- Mensaje original -----
> De: "Alessandro Ferrucci" <alessandroferrucci@gmail.com>
> Para: pgsql-performance@postgresql.org
> Enviados: Miércoles, 26 de Abril 2017 0:19:37
> Asunto: Re: [PERFORM] Slow query with 3 table joins
>
>
>
> After about 40 inutes the slow query finally finished and the result
> of the EXPLAIN plan can be found here:
>
>
> https://explain.depesz.com/s/BX22
>
>
> Thanks,
> Alessandro Ferrucci
1) Looking at the "Rows removed by filter" in that explain, looks like a selectivity issue: Many (many many) rows are
fetched,just to be rejected later.
I think you can try a partial index on ''field (unit_id) where field_name="SHEETS_PRESENT"'', if it is practical to
you.
See https://www.postgresql.org/docs/current/static/indexes-partial.html for a good read about partial indexes.
2) 9.2 is a pretty old version of PG. If you are migrating yet, you should consider a more recent version
HTH
Gerardo
