Horton

Re: ICU locale validation / canonicalization

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2023-05-02T14:29:38Z
Lists: pgsql-hackers 
On Thu, Mar 30, 2023 at 08:59:41AM +0200, Peter Eisentraut wrote:
> On 30.03.23 04:33, Jeff Davis wrote:
> >Attached is a new version of the final patch, which performs
> >canonicalization. I'm not 100% sure that it's wanted, but it still
> >seems like a good idea to get the locales into a standard format in the
> >catalogs, and if a lot more people start using ICU in v16 (because it's
> >the default), then it would be a good time to do it. But perhaps there
> >are risks?
> 
> I say, let's do it.

The following is not cause for postgresql.git changes at this time, but I'm
sharing it in case it saves someone else the study effort.  Commit ea1db8a
("Canonicalize ICU locale names to language tags.") slowed buildfarm member
hoverfly, but that disappears if I drop debug_parallel_query from its config.
Typical end-to-end duration rose from 2h5m to 2h55m.  Most-affected were
installcheck runs, which rose from 11m to 19m.  (The "check" stage uses
NO_LOCALE=1, so it changed less.)  From profiles, my theory is that each of
the many parallel workers burns notable CPU and I/O opening its ICU collator
for the first time.  debug_parallel_query, by design, pursues parallelism
independent of cost, so this is working as intended.  If it ever matters in
non-debug configurations, we might raise the default parallel_setup_cost or
pre-load ICU collators in the postmaster.

Commits

  1. Add missing source file to nls.mk

  2. Fix MSVC warning introduced in ea1db8ae70.

  3. Canonicalize ICU locale names to language tags.

  4. Validate ICU locales.

  5. initdb: emit message when using default ICU locale.

  6. initdb: replace check_icu_locale() with default_icu_locale().

  7. Fix error inconsistency in older ICU versions.

  8. Avoid potential UCollator leak for older ICU versions.

  9. pg_locale.c: change ereport() to elog().

  10. Handle the "und" locale in ICU versions 54 and older.

  11. Wrap ICU ucol_open().

  12. Support language tags in older ICU versions (53 and earlier).

  13. Improve support for UNICODE collation on older ICU

  14. Use ICU by default at initdb time.