Re: [INTERFACES] (libpq question) Holy cow, what's all this fluff?!

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От Matthew Hagerty
Тема Re: [INTERFACES] (libpq question) Holy cow, what's all this fluff?!
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Msg-id 4.1.19990214140611.00950100@mail.venux.net
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Ответы Re: [INTERFACES] (libpq question) Holy cow, what's all this fluff?!  (Tom Lane <tgl@sss.pgh.pa.us>)
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At 01:45 PM 2/14/99 -0500, Tom Lane wrote:
>Matthew Hagerty <matthew@venux.net> writes:
>> At 04:30 AM 2/14/99 +0000, Thomas G. Lockhart wrote:
>>>> You want a varchar (or is it bpchar?), not a char. char(x) will always
>>>> return x characters, with space padding if necessary.
>
>> Yeah, but the docs say you get a performance hit for using varchar, text,
>> and the like.  Which is worse, the database performance hit or the extra
>> call to trim for every char field?
>
>Whatever docs you are looking at are obsolete.  char(n), varchar(n), and
>text have essentially interchangeable performance and representation.
>They all have a length word and some characters.
>
>(I've griped about that myself --- particularly that plain "char" is
>effectively an 8-byte field, not a 1-byte field like you'd expect.
>Nobody else seems worried about it though.)
>
>I'd recommend using "text", personally, unless you have a specific
>reason for imposing an upper length limit on the string.
>
>            regards, tom lane

The docs that mention the performance hit were really the FAQ, item 3.10.
Check it out.  Also, item 3.8 mentions psql's \do command, however when I
type \do nothing happens and I have to ctrl-c to get the prompt back.  Any
suggestions?  All I need to do is a case-insensitive query.

Thanks,
Matthew




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