Re: Nested loop and simple join query - slow after upgrade to 9.2

On Fri, Jan 25, 2013 at 7:34 AM, alexandre - aldeia digital
<adaldeia@gmail.com> wrote:
> Hi,
>
> Last weekend, we upgrade a PG from 8.4 to 9.2 version (full
> pg_dump/restore/vacuum/analyze). After this, some simple join querys
> became very slow, maybe because the use of nested loops. Bellow, an example
> with nestedloop on and off:

What happens if you bump up default_statistics_target by a factor of
10 or 100 and redo the analyze?

Here it is finding 39 times more rows than expected:

Index Scan using ad_pc13t3_modpadrao on pc13t3 t1 (cost=0.00..6.21
rows=1 width=65) (actual time=0.090..0.252 rows=39 loops=1)

It would interesting to know why that is.

Cheers,

Jeff