From: Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
To: pgsql-hackers@postgresql.org, pgsql-general <pgsql-general@postgresql.org>
To: pgsql-performance@postgresql.org
Subject: Re: [pgsql-performance] Large databases, performance
Date: Wed, 09 Oct 2002 19:11:09 +0530
Message-ID: <3DA47F4D.12909.1AAA876E@localhost> (raw)
In-Reply-To: <19697.1034170370@sss.pgh.pa.us>
References: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com>
On 9 Oct 2002 at 9:32, Tom Lane wrote:
> Manfred Koizar <mkoi-pg@aon.at> writes:
> > here is an implementation of a set of user types: char3, char4,
> > char10.
>
> Coupla quick comments on these:
>
> > CREATE FUNCTION charNN_lt(charNN, charNN)
> > RETURNS boolean
> > AS '$libdir/fixchar'
> > LANGUAGE 'c';
>
> > bool
> > charNN_lt(char *a, char *b)
> > {
> > return (strncmp(a, b, NN) < 0);
> > }/*charNN_lt*/
>
> These functions are dangerous as written, because they will crash on
> null inputs. I'd suggest marking them strict in the function
> declarations. Some attention to volatility declarations (isCachable
> or isImmutable) would be a good idea too.
Let me add something. Using char* is bad idea. I had faced a situation recently
on HP-UX 11 that with a libc patch, isspace collapsed for char>127. Fix was to
use unsigned char. There are other places also where the input character is
used as index to an array internally and can cause weird behaviour for values
>127
I will apply both the correction here. Will post the final stuff soon.
Bye
Shridhar
--
Hacker's Quicky #313: Sour Cream -n- Onion Potato Chips Microwave Egg Roll
Chocolate Milk
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To: pgsql-sql@postgresql.org
Cc: shridhar_daithankar@persistent.co.in, pgsql-general@postgresql.org, pgsql-performance@postgresql.org
Subject: Re: [pgsql-performance] Large databases, performance
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