Re: What is the impact of "varchar_pattern_ops" on performance and/or memory

Em 22/01/2013 18:04, Tom Lane escreveu:
> Edson Richter <edsonrichter@hotmail.com> writes:
>> Almost all indexed columns of kind varchar in my database require
>> "varchar_pattern_ops" op class in order to make my LIKE queries more
>> optmized.
>> Is there any way to define that this operator class is the default for
>> my database for varchar columns?
> No.  (Well, you could go and hack the catalog entries to mark it as the
> default, but things would fail rather badly whenever you dump and reload
> the database, because pg_dump won't dump changes to built-in objects.)

Can I change this in template database, and then get the benefit of
having these changes propagated to newly created databases?

>
>> What would be the impact in terms of performance and memory consumption?
> It's probably cheaper, actually, than the regular strcoll-based
> comparisons.
>
> BTW, have you considered whether you could run your database in C locale
> and thus dodge the whole problem?  In C locale there's no difference
> between this opclass and text_ops.

Using C locale, would I face problems with Portuguese Brazilian
characters like ã, ç, é?

Thanks, Tom!


Edson

>
>             regards, tom lane
>
>