Horton

Re: insensitive collations

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Daniel Verite <daniel@manitou-mail.org>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-12-19T21:41:48Z
Lists: pgsql-hackers 
Peter Geoghegan <pg@bowt.ie> writes:
> The Unicode consortium calls our current behavior within comparisons
> "deterministic comparisons" -- it's something they're not so keen on:
> https://unicode.org/reports/tr10/#Deterministic_Comparison
> I suggest using their terminology for our current behavior.

Hm, it's not the greatest terminology perhaps, but if they're using it
then that makes it at least semi-standard.  I can live with that.

> FWIW, I don't think that your IEEE analogy quite works, because you're
> talking about a property of a datatype. A collation is not intrinsic
> to any collatable datatype. Fortunately, we're not required to agree
> on what feels natural.

Right, which is exactly why it'd be a bad idea to use "natural" as the
name for this property ...

			regards, tom lane

Commits

  1. Collations with nondeterministic comparison

  2. Add support for collation attributes on older ICU versions

  3. Make type "name" collation-aware.

  4. Make collation-aware system catalog columns use "C" collation.

  5. Adjust string comparison so that only bitwise-equal strings are considered