Horton

Re: Identifying no-op length coercions

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Jim Nasby <jim@nasby.net>
Cc: Alexey Klyukin <alexk@commandprompt.com>, Noah Misch <noah@leadboat.com>, Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
Date: 2011-06-03T16:13:44Z
Lists: pgsql-hackers 
On Fri, Jun 3, 2011 at 11:43 AM, Jim Nasby <jim@nasby.net> wrote:
> On Jun 3, 2011, at 10:11 AM, Alexey Klyukin wrote:
>>> Is your interest in cheap varchar(N)->varchar(N+M) conversions specifically, or
>>> in some broader application of this facility?
>>
>> Exactly varchar conversions.
>
> Why limit it to varchar? Shouldn't we be able to do this for any varlena? The only challenge I see is numeric; we'd need to ensure that both size and precision are not decreasing.

More than that: you should also be able to make it work for things
like xml -> text.

Indeed, I believe Noah has plans to do just that.

Which, quite frankly, will be awesome.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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