Re: Slow query with 3 table joins

----- Mensaje original -----
> De: "Alessandro Ferrucci" <alessandroferrucci(at)gmail(dot)com>
> Para: pgsql-performance(at)postgresql(dot)org
> Enviados: Miércoles, 26 de Abril 2017 0:19:37
> Asunto: Re: [PERFORM] Slow query with 3 table joins
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>
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> After about 40 inutes the slow query finally finished and the result
> of the EXPLAIN plan can be found here:
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> https://explain.depesz.com/s/BX22
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> 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