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Re: AW: [HACKERS] varchar() vs char16 performance

From: "Thomas G(dot) Lockhart" <lockhart(at)alumni(dot)caltech(dot)edu>
To: Zeugswetter Andreas <andreas(dot)zeugswetter(at)telecom(dot)at>
Cc: "'pgsql-hackers(at)hub(dot)org'" <pgsql-hackers(at)hub(dot)org>
Subject: Re: AW: [HACKERS] varchar() vs char16 performance
Date: 1998-03-19 17:27:38
Message-ID: (view raw, whole thread or download thread mbox)
Lists: 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/' 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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