Re: simplify regular expression locale global variables

On 10/15/24 8:12 AM, Peter Eisentraut wrote:
> We currently have
> 
>      static PG_Locale_Strategy pg_regex_strategy;
>      static pg_locale_t pg_regex_locale;
>      static Oid  pg_regex_collation;
> 
> but after the recent improvements to pg_locale_t handling, we don't need 
> all three anymore.  All the information we have is contained in 
> pg_locale_t, so we just need to keep that one.  This allows us to 
> structure the locale-using regular expression code more similar to other 
> locale-using code, mainly by provider, avoiding another layer that is 
> specific only to the regular expression code.  The first patch 
> implements that.

Jeff Davis has a patch which also fixes this while refactoring other 
stuff too which I prefer over your patch since it also cleans up the 
collation code in general.

https://www.postgresql.org/message-id/2830211e1b6e6a2e26d845780b03e125281ea17b.camel%40j-davis.com

> The second patch removes a call to pg_set_regex_collation() that I think 
> is unnecessary.
> 
> The third patch adds a pg_unset_regex_collation() call that undoes what 
> pg_set_regex_collation() does.  I mainly used this to verify the second 
> patch, but maybe it's also useful on its own, not sure.
> 
> (I don't have any plans to get rid of the remaining global variable. 
> That would certainly be nice from an intellectual point of view, but 
> fiddling this into the regular expression code looks quite messy.  In 
> any case, it's probably easier with one variable instead of three, if 
> someone wants to try.)

I have not looked at your other two patches yet.

Andreas