Re: Seeing foreign key lookups in explain output
От | Vincent de Phily |
---|---|
Тема | Re: Seeing foreign key lookups in explain output |
Дата | |
Msg-id | 1954268.IazUjRs8Ax@moltowork обсуждение исходный текст |
Ответ на | Re: Seeing foreign key lookups in explain output (Marti Raudsepp <marti@juffo.org>) |
Список | pgsql-general |
On Tuesday 20 September 2011 16:32:50 Marti Raudsepp wrote: > On Tue, Sep 20, 2011 at 16:12, Marti Raudsepp <marti@juffo.org> wrote: > > +1 for a TODO on adding foreign key trigger time to EXPLAIN ANALYZE > > output. > Sorry, that was too hasty. We already have that now in 9.0 and 9.1 > (not sure when it was introduced) > > create table a as select generate_series(1,10000) i; > create table b as select generate_series(1,10000) i; > alter table a add primary key (i); > alter table b add foreign key (i) references a (i) on delete cascade; > explain analyze delete from a; > > QUERY PLAN > --------------------------------------------------------------------------- > -------------------------------- Delete (cost=0.00..145.00 rows=10000 > width=6) (actual > time=16.308..16.308 rows=0 loops=1) > -> Seq Scan on a (cost=0.00..145.00 rows=10000 width=6) (actual > time=0.008..2.208 rows=10000 loops=1) > Trigger for constraint b_i_fkey: time=6324.652 calls=10000 > Total runtime: 6342.406 ms > > Notice the line "Trigger for constraint b_i_fkey" Ahhh I never spoted that in the changelogs, and haven't upgraded yet. Great :) Yet another reason to upgrade ASAP. Thanks. -- Vincent de Phily
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