Re: using an index worst performances

Richard Huxton wrote:

> Gaetano Mendola wrote:
>
>> Hi all,
>> I'm tring to optimize the following query:
>>
>> http://rafb.net/paste/results/YdO9vM69.html
>>
>> as you can see from the explain after defining the
>> index the performance is worst.
>>
>> If I raise the default_statistic_target to 200
>> then the performance are worst then before:
>>
>>
>> Without index: 1.140 ms
>> With index: 1.400 ms
>> With default_statistic_targer = 200:   1.800 ms
>
>
> Can I just check that 1.800ms means 1.8 secs (You're using . as the
> thousands separator)?
>
> If it means 1.8ms then frankly the times are too short to mean anything
> without running them 100 times and averaging.


It mean 1.8 ms and that execution time is sticky to that value even
with 1000 times.


Regards
Gaetano Mendola