Re: New cast between inet/cidr and bytea

From: Zoltan Boszormenyi <zb(at)cybertec(dot)at>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Bruce Momjian <bruce(at)momjian(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: New cast between inet/cidr and bytea
Date: 2007-05-31 16:03:12
Message-ID: 465EF1C0.6000308@cybertec.at
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Tom Lane írta:
> Zoltan Boszormenyi <zb(at)cybertec(dot)at> writes:
>
>> Bruce Momjian írta:
>>
>>> What is the use case for such a cast?
>>>
>
>
>> The application doesn't want to parse the textual IP address
>> when all the parsing and checking intelligence is already there
>> in the inet/cidr type checks.
>>
>
> This presumes exactly the assumption we are questioning, namely that
> there's a universal binary representation for these things.

But there is: network order.

> There might
> be such for bare IP addresses (ignoring endianness) but the argument
> doesn't scale to CIDR.

Would you enlighten me why not?

> You've also failed to make the case that this
> application designer has made a sane judgment about whether avoiding
> parsing is a good tradeoff here.
>

So, reinventing the wheel is always the way to go?
Even when the app is actually storing those IP addresses
with the type and features PostgreSQL provides?

> Also: to the extent that the application is willing to deal with a
> Postgres-specific inet/cidr representation (which, in the end, is
> what this would be) it can do that *today* using binary output format.
> So I'm still not seeing an argument for exposing a cast to bytea.
>
> regards, tom lane
>

But the binary output of inet/cidr needs another round of parsing
which requires using internal server headers.

Would you like a 4/8/16/32 byte output using IP only
or IP + fully represented netmask better?

Best regards,

--
----------------------------------
Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/

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