Em 04/12/2012 11:50, Pavel Stehule escreveu:
> Hello
>
> 2012/12/4 Edson Richter <edsonrichter@hotmail.com>:
>> I think I already know the answer (char(14)), but I would like to confirm:
>> which is faster?
>>
>> In Brazil, company id has 14 digits (12 identifiers, 2 control digits). By
>> today, application use varchar(14) for these, but I intend to optimize
>> insert/update/delete and search, and I'm considering to change it to
>> char(14).
>>
>> Will it give ANY gain? I do use equality and like operators for search.
>>
> There are no big differences between char and varchar - char can be
> little bit slower, because empty chars to limit are filled by space.
> So usually varchar is more effective (in PostgreSQL).
In this specific case, the full length (14) is mandatory... so seems
there is no loss or gain.
Also, I see all varchar(...) created are by default "storage = EXTENDED"
(from "Pg Admin"), while other datatypes (like numeric, smallint,
integer) are "storage = MAIN".
Can I have a gain using fixed length datatype in place of current
varchar (like "numeric (14,0)")?
Or changing to "char(14) check length(doc)=14" and "storage=MAIN"?
Sorry if there are many questions in one, but I'm in a brainstorm...
Thanks,
Edson
>
> Regards
>
> Pavel Stehule
>
>
>> Regards,
>>
>> Edson
>>
>>
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