Re: Does this matter?
От | Wei Weng |
---|---|
Тема | Re: Does this matter? |
Дата | |
Msg-id | 1036183942.25096.3.camel@Monet обсуждение исходный текст |
Ответ на | Re: Does this matter? (Josh Berkus <josh@agliodbs.com>) |
Ответы |
Re: Does this matter?
Re: Does this matter? |
Список | pgsql-performance |
Josh: Since I need to use a GUID as the primary key, I have to use the char datatype. On Fri, 2002-11-01 at 15:23, Josh Berkus wrote: > Wei, > > > Does it make a performance difference if I use a char(20) or a char(36) > > as the primary key? My thought is no, but I would like to hear more > > opinions. > > Yes, it does, though probably minor unless you have millions of records. CHAR > is padded out to the specified length. Therefore the index on a char(36) > column will be a little larger, and thus a little slower, than the char(20). Does it affect the INSERT/UPDATE/DELETE operations on tables or simply the SELECT operation or both? > > Now, there would be no difference between VARCHAR(20) and VARCHAR(36) unless > you used some of the extra 16 characters on most rows. > > Either way, for tables of a few thousand records, I doubt that you'll notice > the difference. BTW, why not use a SERIAL value as a surrogate primary key? > > > And a little further off topic(since we have many database experts > > here), does it matter on MS SQL server 7? > > Yes, same reason. -- Wei Weng Network Software Engineer KenCast Inc.
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