Re: An idea on faster CHAR field indexing - Mailing list pgsql-hackers

From Giles Lean
Subject Re: An idea on faster CHAR field indexing
Date
Msg-id 12860.961674100@nemeton.com.au
Whole thread Raw
In response to Re: An idea on faster CHAR field indexing  ("Randall Parker" <randall@nls.net>)
List pgsql-hackers
[ I hope this is useful for the archives, even though it's pretty much been covered already. --giles ]

> With Unicode you have to have a collation order that cuts across
> what use to be separate character sets in separate code pages.

From the glossary at http://www.unicode.org/glossary/index.html:

Collation   The process of ordering units of textual information. Collation is   usually specific to a particular
language.Also known as   alphabetizing or alphabetic sorting. Unicode Technical Report #10,   "Unicode Collation
Algorithm,"defines a complete, unambiguous,   specified ordering for all characters in the Unicode Standard.
 

The "Unicode Technical Report #10" is accessible at:

http://www.unicode.org/unicode/reports/tr10/

This technical report provides a way to specify "the tailoring for any
particular country" which together with the standard ordering will
allow different Unicode implementations to sort any particular input
identically.

Summary is that Unicode still has locales and we still have to know
not only the character set/code page but also the locale ("country
specific tailoring") an index was created with to use it.

Regards,

Giles



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