Change collate and ctype fields to type text

This changes the data type of the catalog fields datcollate, datctype,
collcollate, and collctype from name to text.  There wasn't ever a
really good reason for them to be of type name; presumably this was
just carried over from when they were fixed-size fields in pg_control,
first into the corresponding pg_database fields, and then to
pg_collation.  The values are not identifiers or object names, and we
don't ever look them up that way.

Changing to type text saves space in the typical case, since locale
names are typically only a few bytes long.  But it is also possible
that an ICU locale name with several customization options appended
could be longer than 63 bytes, so this also enables that case, which
was previously probably broken.

Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5e756dd6-0e91-d778-96fd-b1bcb06c161a@2ndquadrant.com

1 files changed, 28 insertions, 13 deletions

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 56748551ded..12fc2316f97 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -129,18 +129,30 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 	{
 		Oid			collid;
 		HeapTuple	tp;
+		Datum		datum;
+		bool		isnull;
 
 		collid = get_collation_oid(defGetQualifiedName(fromEl), false);
 		tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collid));
 		if (!HeapTupleIsValid(tp))
 			elog(ERROR, "cache lookup failed for collation %u", collid);
 
-		collcollate = pstrdup(NameStr(((Form_pg_collation) GETSTRUCT(tp))->collcollate));
-		collctype = pstrdup(NameStr(((Form_pg_collation) GETSTRUCT(tp))->collctype));
 		collprovider = ((Form_pg_collation) GETSTRUCT(tp))->collprovider;
 		collisdeterministic = ((Form_pg_collation) GETSTRUCT(tp))->collisdeterministic;
 		collencoding = ((Form_pg_collation) GETSTRUCT(tp))->collencoding;
 
+		datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_collcollate, &isnull);
+		if (!isnull)
+			collcollate = TextDatumGetCString(datum);
+		else
+			collcollate = NULL;
+
+		datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_collctype, &isnull);
+		if (!isnull)
+			collctype = TextDatumGetCString(datum);
+		else
+			collctype = NULL;
+
 		ReleaseSysCache(tp);
 
 		/*
@@ -314,7 +326,7 @@ AlterCollation(AlterCollationStmt *stmt)
 	Oid			collOid;
 	HeapTuple	tup;
 	Form_pg_collation collForm;
-	Datum		collversion;
+	Datum		datum;
 	bool		isnull;
 	char	   *oldversion;
 	char	   *newversion;
@@ -332,11 +344,12 @@ AlterCollation(AlterCollationStmt *stmt)
 		elog(ERROR, "cache lookup failed for collation %u", collOid);
 
 	collForm = (Form_pg_collation) GETSTRUCT(tup);
-	collversion = SysCacheGetAttr(COLLOID, tup, Anum_pg_collation_collversion,
-								  &isnull);
-	oldversion = isnull ? NULL : TextDatumGetCString(collversion);
+	datum = SysCacheGetAttr(COLLOID, tup, Anum_pg_collation_collversion, &isnull);
+	oldversion = isnull ? NULL : TextDatumGetCString(datum);
 
-	newversion = get_collation_actual_version(collForm->collprovider, NameStr(collForm->collcollate));
+	datum = SysCacheGetAttr(COLLOID, tup, Anum_pg_collation_collcollate, &isnull);
+	Assert(!isnull);
+	newversion = get_collation_actual_version(collForm->collprovider, TextDatumGetCString(datum));
 
 	/* cannot change from NULL to non-NULL or vice versa */
 	if ((!oldversion && newversion) || (oldversion && !newversion))
@@ -383,8 +396,9 @@ pg_collation_actual_version(PG_FUNCTION_ARGS)
 {
 	Oid			collid = PG_GETARG_OID(0);
 	HeapTuple	tp;
-	char	   *collcollate;
 	char		collprovider;
+	Datum		datum;
+	bool		isnull;
 	char	   *version;
 
 	tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collid));
@@ -393,12 +407,13 @@ pg_collation_actual_version(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_UNDEFINED_OBJECT),
 				 errmsg("collation with OID %u does not exist", collid)));
 
-	collcollate = pstrdup(NameStr(((Form_pg_collation) GETSTRUCT(tp))->collcollate));
 	collprovider = ((Form_pg_collation) GETSTRUCT(tp))->collprovider;
 
-	ReleaseSysCache(tp);
+	datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_collcollate, &isnull);
+	Assert(!isnull);
+	version = get_collation_actual_version(collprovider, TextDatumGetCString(datum));
 
-	version = get_collation_actual_version(collprovider, collcollate);
+	ReleaseSysCache(tp);
 
 	if (version)
 		PG_RETURN_TEXT_P(cstring_to_text(version));
@@ -546,7 +561,7 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 #ifdef READ_LOCALE_A_OUTPUT
 	{
 		FILE	   *locale_a_handle;
-		char		localebuf[NAMEDATALEN]; /* we assume ASCII so this is fine */
+		char		localebuf[LOCALE_NAME_BUFLEN];
 		int			nvalid = 0;
 		Oid			collid;
 		CollAliasData *aliases;
@@ -570,7 +585,7 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 		{
 			size_t		len;
 			int			enc;
-			char		alias[NAMEDATALEN];
+			char		alias[LOCALE_NAME_BUFLEN];
 
 			len = strlen(localebuf);