Re: What is the maximum encoding-conversion growth rate, anyway? - Mailing list pgsql-hackers

From Michael Fuhr
Subject Re: What is the maximum encoding-conversion growth rate, anyway?
Date
Msg-id 20070529143411.GA70525@winnie.fuhr.org
Whole thread Raw
In response to Re: What is the maximum encoding-conversion growth rate, anyway?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Tue, May 29, 2007 at 10:00:06AM -0400, Tom Lane wrote:
> In practice though, I find it hard to imagine a pair of encodings for
> which the growth rate is more than 3x.  You'd need something that
> translates a single-byte character into 4 or more bytes (pretty
> unlikely, especially considering we require all these encodings to be
> ASCII supersets); or something that translates a 2-byte character into
> more than 6 bytes.

Many characters in the 0x80..0xff range of single-byte encodings
like LATIN1 become four bytes in GB18030 (e.g., LATIN1 f1 = GB18030
81 30 8a 39).  PostgreSQL doesn't currently support such conversions
but it's something to be aware of.

-- 
Michael Fuhr


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