Re: [RFC] new digest datatypes, or generic fixed-len hex types?

On Mon, Jul 27, 2009 at 12:02 PM, Andrew Dunstan<andrew@dunslane.net> wrote:
> Merlin Moncure wrote:
>>
>> On Mon, Jul 27, 2009 at 10:20 AM, Tom Lane<tgl@sss.pgh.pa.us> wrote:
>>
>>>
>>> Alvaro Herrera <alvherre@commandprompt.com> writes:
>>>
>>>>
>>>> We've developed some code to implement fixed-length datatypes for well
>>>> known digest function output (MD5, SHA1 and the various SHA2 types).
>>>> These types have minimal overhead and are quite complete, including
>>>> btree and hash opclasses.
>>>>      We're wondering about proposing them for inclusion in pgcrypto.
>>>>
>>>
>>> Wasn't this proposed and rejected before?  (Or more to the point,
>>> why'd you bother?  The advantage over bytea seems negligible.)
>>>
>>
>> well, one nice things about the fixed length types is that you can
>> keep your table from needing a toast table when you have a bytea in
>> it.
>
> Can't you just set storage on the column to MAIN to stop it being stored in
> a toast table?

of course.

hm. would the input/output functions for the fixed length types be
faster?  what is the advantage of the proposal?

merlin