Add option to use ICU as global locale provider

This adds the option to use ICU as the default locale provider for
either the whole cluster or a database.  New options for initdb,
createdb, and CREATE DATABASE are used to select this.

Since some (legacy) code still uses the libc locale facilities
directly, we still need to set the libc global locale settings even if
ICU is otherwise selected.  So pg_database now has three
locale-related fields: the existing datcollate and datctype, which are
always set, and a new daticulocale, which is only set if ICU is
selected.  A similar change is made in pg_collation for consistency,
but in that case, only the libc-related fields or the ICU-related
field is set, never both.

Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5e756dd6-0e91-d778-96fd-b1bcb06c161a%402ndquadrant.com

1 files changed, 64 insertions, 33 deletions

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 93df1d366c6..346f85f05ea 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -65,6 +65,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 	DefElem    *versionEl = NULL;
 	char	   *collcollate;
 	char	   *collctype;
+	char	   *colliculocale;
 	bool		collisdeterministic;
 	int			collencoding;
 	char		collprovider;
@@ -152,6 +153,12 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 		else
 			collctype = NULL;
 
+		datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_colliculocale, &isnull);
+		if (!isnull)
+			colliculocale = TextDatumGetCString(datum);
+		else
+			colliculocale = NULL;
+
 		ReleaseSysCache(tp);
 
 		/*
@@ -172,18 +179,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 
 		collcollate = NULL;
 		collctype = NULL;
-
-		if (localeEl)
-		{
-			collcollate = defGetString(localeEl);
-			collctype = defGetString(localeEl);
-		}
-
-		if (lccollateEl)
-			collcollate = defGetString(lccollateEl);
-
-		if (lcctypeEl)
-			collctype = defGetString(lcctypeEl);
+		colliculocale = NULL;
 
 		if (providerEl)
 			collproviderstr = defGetString(providerEl);
@@ -211,15 +207,42 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 		else
 			collprovider = COLLPROVIDER_LIBC;
 
-		if (!collcollate)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-					 errmsg("parameter \"lc_collate\" must be specified")));
+		if (localeEl)
+		{
+			if (collprovider == COLLPROVIDER_LIBC)
+			{
+				collcollate = defGetString(localeEl);
+				collctype = defGetString(localeEl);
+			}
+			else
+				colliculocale = defGetString(localeEl);
+		}
 
-		if (!collctype)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-					 errmsg("parameter \"lc_ctype\" must be specified")));
+		if (lccollateEl)
+			collcollate = defGetString(lccollateEl);
+
+		if (lcctypeEl)
+			collctype = defGetString(lcctypeEl);
+
+		if (collprovider == COLLPROVIDER_LIBC)
+		{
+			if (!collcollate)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+						 errmsg("parameter \"lc_collate\" must be specified")));
+
+			if (!collctype)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+						 errmsg("parameter \"lc_ctype\" must be specified")));
+		}
+		else if (collprovider == COLLPROVIDER_ICU)
+		{
+			if (!colliculocale)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+						 errmsg("parameter \"locale\" must be specified")));
+		}
 
 		/*
 		 * Nondeterministic collations are currently only supported with ICU
@@ -260,7 +283,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 	}
 
 	if (!collversion)
-		collversion = get_collation_actual_version(collprovider, collcollate);
+		collversion = get_collation_actual_version(collprovider, collprovider == COLLPROVIDER_ICU ? colliculocale : collcollate);
 
 	newoid = CollationCreate(collName,
 							 collNamespace,
@@ -270,6 +293,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 							 collencoding,
 							 collcollate,
 							 collctype,
+							 colliculocale,
 							 collversion,
 							 if_not_exists,
 							 false);	/* not quiet */
@@ -352,8 +376,9 @@ AlterCollation(AlterCollationStmt *stmt)
 	datum = SysCacheGetAttr(COLLOID, tup, Anum_pg_collation_collversion, &isnull);
 	oldversion = isnull ? NULL : TextDatumGetCString(datum);
 
-	datum = SysCacheGetAttr(COLLOID, tup, Anum_pg_collation_collcollate, &isnull);
-	Assert(!isnull);
+	datum = SysCacheGetAttr(COLLOID, tup, collForm->collprovider == COLLPROVIDER_ICU ? Anum_pg_collation_colliculocale : Anum_pg_collation_collcollate, &isnull);
+	if (isnull)
+		elog(ERROR, "unexpected null in pg_collation");
 	newversion = get_collation_actual_version(collForm->collprovider, TextDatumGetCString(datum));
 
 	/* cannot change from NULL to non-NULL or vice versa */
@@ -414,9 +439,15 @@ pg_collation_actual_version(PG_FUNCTION_ARGS)
 
 	collprovider = ((Form_pg_collation) GETSTRUCT(tp))->collprovider;
 
-	datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_collcollate, &isnull);
-	Assert(!isnull);
-	version = get_collation_actual_version(collprovider, TextDatumGetCString(datum));
+	if (collprovider != COLLPROVIDER_DEFAULT)
+	{
+		datum = SysCacheGetAttr(COLLOID, tp, collprovider == COLLPROVIDER_ICU ? Anum_pg_collation_colliculocale : Anum_pg_collation_collcollate, &isnull);
+		if (isnull)
+			elog(ERROR, "unexpected null in pg_collation");
+		version = get_collation_actual_version(collprovider, TextDatumGetCString(datum));
+	}
+	else
+		version = NULL;
 
 	ReleaseSysCache(tp);
 
@@ -643,7 +674,7 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 			 */
 			collid = CollationCreate(localebuf, nspid, GetUserId(),
 									 COLLPROVIDER_LIBC, true, enc,
-									 localebuf, localebuf,
+									 localebuf, localebuf, NULL,
 									 get_collation_actual_version(COLLPROVIDER_LIBC, localebuf),
 									 true, true);
 			if (OidIsValid(collid))
@@ -704,7 +735,7 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 
 			collid = CollationCreate(alias, nspid, GetUserId(),
 									 COLLPROVIDER_LIBC, true, enc,
-									 locale, locale,
+									 locale, locale, NULL,
 									 get_collation_actual_version(COLLPROVIDER_LIBC, locale),
 									 true, true);
 			if (OidIsValid(collid))
@@ -745,7 +776,7 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 			const char *name;
 			char	   *langtag;
 			char	   *icucomment;
-			const char *collcollate;
+			const char *iculocstr;
 			Oid			collid;
 
 			if (i == -1)
@@ -754,20 +785,20 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 				name = uloc_getAvailable(i);
 
 			langtag = get_icu_language_tag(name);
-			collcollate = U_ICU_VERSION_MAJOR_NUM >= 54 ? langtag : name;
+			iculocstr = U_ICU_VERSION_MAJOR_NUM >= 54 ? langtag : name;
 
 			/*
 			 * Be paranoid about not allowing any non-ASCII strings into
 			 * pg_collation
 			 */
-			if (!pg_is_ascii(langtag) || !pg_is_ascii(collcollate))
+			if (!pg_is_ascii(langtag) || !pg_is_ascii(iculocstr))
 				continue;
 
 			collid = CollationCreate(psprintf("%s-x-icu", langtag),
 									 nspid, GetUserId(),
 									 COLLPROVIDER_ICU, true, -1,
-									 collcollate, collcollate,
-									 get_collation_actual_version(COLLPROVIDER_ICU, collcollate),
+									 NULL, NULL, iculocstr,
+									 get_collation_actual_version(COLLPROVIDER_ICU, iculocstr),
 									 true, true);
 			if (OidIsValid(collid))
 			{