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

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: darrenk(at)insightdist(dot)com (Darren King)
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: AW: [HACKERS] varchar() vs char16 performance
Date: 1998-03-19 19:57:13
Message-ID: 199803191957.OAA14730@candle.pha.pa.us
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>
> > 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.
> >
>
> The char[248] types rip out just fine.
>
> But that char16 is a whole new beast. It's tentacles are everywhere...
>
> >From comments in various files, the char16 was the original name type
> and was then replaced with 'name'. But there are still a few places
> of inconsistency in the code, namely (*bad pun*) in the cache code.

Yes, you are correct. That was the original name length.

I thought I fixed all the cache name16 references before 6.3. That is
why we can now have index names over 16 characters. Can you confirm
this is still a problem in 6.3.

>
> There is this eqproc array in catcache.c that is a hack that has to
> match the oids of the types from oid 16 to 30, except that F_CHAR16EQ
> is still where F_NAMEEQ should be. Tried renaming it last night, but
> initdb would blowup the first insert, so there is some other effect in
> the caching code.
>
> Still other incomplete conversions. In pg_proc.h the arg types for
> char16eq, lt, le, gt, ge & ne are names (oid 19) when they should be
> char16 (oid 20)! But char16eq is correctly defined to take char16
> in pg_operator.h.
>
> I'll work on this some more tonite.

Great.

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