Re: full join in view

Tambet Matiisen wrote:

> You are right. After disabling seq_scan, it uses indexes just as you
> described. Unfortunately my view happens to use subquery:

Don't disable seq_scan - sometimes it is better than indexscan.
I had the same problem as you - find subject "sub-select with aggregate"
on pgsql-sql mailing list dated on 2002-10-23.

In my case exposing fields from subquery solved my problem.

There is one more problem in your query - coalesce, which possibly
disables any indexing in your view. Try to rewrite your view - subquery
shouldn't return dor_kst_id and dor_mat_id null.

Is dor_kst_id the same as kdt_kst_id and as mat_id? After some database
practicing I found, that using the same name in all tables is much more
comfortably

For each material (materjalid) and koostud (koostud) you want to find
some current value (koostude_detaild) and compare it to some sum
(documentid...)?
I'm not sure if I understand well your view, but here is my version of
this view - without subquery:

CREATE OR REPLACE VIEW v_tegelikud_kulud AS

SELECT
koostud.kst_id,
materjalid.mat_id,
sum(dor.kogus * koefitsent::numeric) AS kogus,
sum(dor.kokku) AS kokku,
<fields>
FROM
koostud k ,
materjalid m
left join koostude_detailid kdt
ON (m.mat_id = kdt.kdt_mat_id AND k.kst_id = kdt.kdt_kst_id)
left join dokumentide_read dor
ON (m.mat_id = dor.dor_mat_id AND k.kst_id = dor.dor_kst_id)
left JOIN dokumendid dok
ON (dor.dor_dok_id = dok.dok_id AND dok.tyyp = 30 AND
dok.kinnitaja IS NOT NULL)
group by koostud.kst_id, materjalid.mat_id, <fields>;

One more hint - create two-fields-indexes on koostude_detailid and
dokuemntide_read (kdt_mat_id,kdt_kst_id)

Regards,
Tomasz Myrta