>
>
> On Sun, Oct 11, 2009 at 3:30 PM, Michal Szymanski <
mich20061@gmail.com>
> wrote:
>>
>> We have similar problem and now we are try to find solution. When you
>> execute query on partion there is no sorting - DB use index to
>> retrieve data and if you need let say 50 rows it reads 50 rows using
>> index. But when you execute on parent table query optymizer do this:
>>
>> -> Sort (cost=726844.88..748207.02 rows=8544855 width=37739)
>> (actual time=149864.868..149864.876 rows=50 loops=1)
>>
>> it means 8544855 rows should be sorted and it takes long minutes.
>
> The figures in first parenthesis are estimates, not the actual row count.
> If you think it is too low, increase statistic target for that column.
It's true that the figures in parentheses are estimates, it's usually