Обсуждение: Re: ways to force index use?

Tom Lane wrote:
> Seth Ladd <seth@picklematrix.net> writes:
> 
>>My Table Columns (all bigints): start, stop, step1, step2, step3
> 
>                     ^^^^^^^^^^^
> 
> 
>>The Query: explain analyze select * from path where start = 653873 or  
>>start = 649967 or stop = 653873 or stop = 649967
> 
> 
>>Does anyone have a suggestion on how to get that query to use an index?  
> 
> 
> Coerce the constants to bigint, for starters.  However, a query that is
> selecting almost 10% of the table, as your example is, probably
> *shouldn't* be using an index.

I think that for 10% is still better and Index scan.
There is around a way to calculate this elbow ?



Regards
Gaetano Mendola