Re: [EXPLAIN] Nested loops

On Friday 09 January 2009 20:00:36 Thomas Pundt wrote:
> Reg Me Please wrote:
> > Here it comes:
> >
> >  Aggregate  (cost=227.59..227.61 rows=1 width=8)
> >    ->  Nested Loop  (cost=0.00..227.34 rows=49 width=8)
> >          ->  Seq Scan on T2  (cost=0.00..1.07 rows=6 width=4)
> >                Filter: (fld1 = 'VEND'::text)
> >          ->  Index Scan using i_T1_partial on T1  (cost=0.00..37.61
> > rows=8 width=8)
> >                Index Cond: ((T1.prod_id = 42) AND (T1.fk1 = T2.fk1))
>
> That's the EXPLAIN output, _not_ EXPLAIN ANALYZE as requested.
>
> Probably statistics aren't up-to-date?
>
> Thomas

Correct!
I changed a value in the WHERE condition to avoid some caching (maybe useless
in this case).

QUERY PLAN

-------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Aggregate  (cost=227.59..227.61 rows=1 width=8) (actual time=151.722..151.723
rows=1 loops=1)
   ->  Nested Loop  (cost=0.00..227.34 rows=49 width=8)  (actual
time=25.157..151.507 rows=44 loops=1)
         ->  Seq Scan on T2  (cost=0.00..1.07 rows=6 width=4) (actual
time=0.015..0.032 rows=6 loops=1)
               Filter: (fld1 = 'VEND'::text)
         ->  Index Scan using i_T1_partial on T1  (cost=0.00..37.61 rows=8
width=8) (actual time=5.435..25.226 rows=7 loops=6)
               Index Cond: ((T1.prod_id = 4242) AND (T1.fk1 = T2.fk1))
 Total runtime: 151.818 ms
(7 rows)


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