Re: [GENERAL] Slow query plan used

Am 01.06.2017 um 14:07 schrieb Wetzel, Juergen (Juergen):
>
> Am 31.05.2017 um 13:27 schrieb Wetzel, Juergen (Juergen):
>>>> Only 130 rows out of the 30000 have ARCHIVED = 0
>>> in this case i would suggest a partial index:
>>> create index  on  (archived) where archived = 0;
>> Thanks, Andreas.
>>
>> Sorry for the confusion about the table names.
>> The hint with the partial index sounds as it could solve the problem. I will test it.
>>
> Hi,
>
> I created now a partial index
> 	create index on document (archived) where archived = '0';

just to be sure: this syntay is wrong, missing index-name. But it seems 
the index is document_archived_idx ...


>
> But result is same as before: a short like expression included in doubled %-signs leads to a fast query plan whereas a longer like expression or use of single %-sign creates a much slower query. Please see below query plans. Most surprisingly to me is the influence of the like expression, especially the doubled %-sign on short expressions. Any other ideas how to speed up that query or what is going on here in general?
>

please consider my plan B) and increase the stats. See my other mail.


Regards, Andreas

-- 
2ndQuadrant - The PostgreSQL Support Company.
www.2ndQuadrant.com