Re: AW: [HACKERS] varchar() vs char16 performance
От | Thomas G. Lockhart |
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Тема | Re: AW: [HACKERS] varchar() vs char16 performance |
Дата | |
Msg-id | 3511558A.CF8A0A83@alumni.caltech.edu обсуждение исходный текст |
Ответ на | AW: [HACKERS] varchar() vs char16 performance (Zeugswetter Andreas <andreas.zeugswetter@telecom.at>) |
Ответы |
Re: AW: [HACKERS] varchar() vs char16 performance
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Список | pgsql-hackers |
> I had thought that char2-16 add _no_ functionality over the char() and > varchar() types; Tatsuo points out at least one capability which they > have. Are there any others? > > They give and take a char * pointer to a C function like > create function upper(char16) > returning char16 as '/u/my/upper.so' language 'sql'; > whereas char() gives a varlena pointer. I don't really see this as a big deal since, for example, only 16 bytes are allocated for a char16, so it is not guaranteed to be zero delimited and you have to make a working copy to use libc functions anyway. Also, that is really an implementation detail or annoyance rather than a user-visible feature. With the macros that are provided for the varlena structure manipulations, things are pretty convenient. Are there more macros which could be helpful here?? - Tom
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