Message-ID: <bba413de-5548-3480-e8f8-1ced562a866b@enterprisedb.com>
Date: Tue, 4 Jan 2022 17:03:10 +0100
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Subject: Re: ICU for global collation
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To: Julien Rouhaud <rjuju123@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>,
 Daniel Verite <daniel@manitou-mail.org>
References: <374f8048-9d87-462c-a8aa-d02ffca6525f@manitou-mail.org>
 <d7060bf1-177c-e0f2-f13f-b857cdd1182e@2ndquadrant.com>
 <525ef44f-52bf-505f-a491-07835d039424@enterprisedb.com>
 <YdOvEAFGbfGY/47A@jrouhaud>
From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
In-Reply-To: <YdOvEAFGbfGY/47A@jrouhaud>
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On 04.01.22 03:21, Julien Rouhaud wrote:
>> @@ -2774,6 +2776,7 @@ dumpDatabase(Archive *fout)
>>   		appendPQExpBuffer(dbQry, "SELECT tableoid, oid, datname, "
>>   						  "(%s datdba) AS dba, "
>>   						  "pg_encoding_to_char(encoding) AS encoding, "
>> +						  "datcollprovider, "
> 
> This needs to be in a new pg 15+ branch, not in the pg 9.3+.

ok

>> -	if (!lc_collate_is_c(collid) && collid != DEFAULT_COLLATION_OID)
>> -		mylocale = pg_newlocale_from_collation(collid);
>> +	if (!lc_collate_is_c(collid))
>> +	{
>> +		if (collid != DEFAULT_COLLATION_OID)
>> +			mylocale = pg_newlocale_from_collation(collid);
>> +		else if (default_locale.provider == COLLPROVIDER_ICU)
>> +			mylocale = &default_locale;
>> +	}
> 
> There are really a lot of places with this new code.  Maybe it could be some
> new function/macro to wrap that for the normal case (e.g. not formatting.c)?

Right, we could just put this into pg_newlocale_from_collation(), but 
the comment there says

  * In fact, they shouldn't call this function at all when they are dealing
  * with the default locale.  That can save quite a bit in hotspots.

I don't know how to assess that.

We could pack this into a macro or inline function if we are concerned 
about this.