[postgis-users] Strange Performance issue

Markus Schaber schabi at logix-tt.com
Fri Oct 14 07:19:14 PDT 2005


Hi, Jerome,

Markus Schaber wrote:

>>         ->  Index Scan using cntry_name_idx on country 
>>(cost=0.00..805.94 rows=209 width=32) (actual time=0.043..0.288 rows=1
> 
>                           ^^^                                        ^^^
> Hmm, that looks as it has a misestimation about the hits in the country
> table, and so chooses a suboptimal query plan, especially as you said
> that the country table had about 200 rows.

Another hint: You could try to create the cntry_name index as UNIQUE.

HTH,
Markus




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