Remove ancient downcasing code from procedural language operations.

A very long time ago, language names were specified as literals rather
than identifiers, so this code was added to do case-folding.  But that
style has ben deprecated for many years so this isn't needed any more.
Language names will still be downcased when specified as unquoted
identifiers, but quoted identifiers or the old style using string
literals will be left as-is.

doc/src/sgml/ref/create_language.sgml

@@ -143,9 +143,8 @@ CREATE [ OR REPLACE ] [ TRUSTED ] [ PROCEDURAL ] LANGUAGE <replaceable class="pa
 
      <listitem>
       <para>
-       The name of the new procedural language.  The language name is
+       The name of the new procedural language.
-       case insensitive. The name must be unique among the languages
+       The name must be unique among the languages in the database.
-       in the database.
       </para>
 
       <para>

src/backend/commands/define.c

@@ -42,19 +42,6 @@
 #include "parser/scansup.h"
 #include "utils/int8.h"
 
-
-/*
- * Translate the input language name to lower case, and truncate if needed.
- *
- * Returns a palloc'd string
- */
-char *
-case_translate_language_name(const char *input)
-{
-	return downcase_truncate_identifier(input, strlen(input), false);
-}
-
-
 /*
  * Extract a string value (otherwise uninterpreted) from a DefElem.
  */

src/backend/commands/functioncmds.c

@@ -779,7 +779,6 @@ CreateFunction(CreateFunctionStmt *stmt, const char *queryString)
 	Oid			prorettype;
 	bool		returnsSet;
 	char	   *language;
-	char	   *languageName;
 	Oid			languageOid;
 	Oid			languageValidator;
 	char	   *funcname;
@@ -828,16 +827,13 @@ CreateFunction(CreateFunctionStmt *stmt, const char *queryString)
 								 &isStrict, &security,
 								 &proconfig, &procost, &prorows);
 
-	/* Convert language name to canonical case */
-	languageName = case_translate_language_name(language);
-
 	/* Look up the language and validate permissions */
-	languageTuple = SearchSysCache1(LANGNAME, PointerGetDatum(languageName));
+	languageTuple = SearchSysCache1(LANGNAME, PointerGetDatum(language));
 	if (!HeapTupleIsValid(languageTuple))
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("language \"%s\" does not exist", languageName),
+				 errmsg("language \"%s\" does not exist", language),
-				 (PLTemplateExists(languageName) ?
+				 (PLTemplateExists(language) ?
 				  errhint("Use CREATE LANGUAGE to load the language into the database.") : 0)));
 
 	languageOid = HeapTupleGetOid(languageTuple);
@@ -906,7 +902,7 @@ CreateFunction(CreateFunctionStmt *stmt, const char *queryString)
 
 	compute_attributes_with_style(stmt->withClause, &isStrict, &volatility);
 
-	interpret_AS_clause(languageOid, languageName, funcname, as_clause,
+	interpret_AS_clause(languageOid, language, funcname, as_clause,
 						&prosrc_str, &probin_str);
 
 	/*
@@ -1964,7 +1960,6 @@ ExecuteDoStmt(DoStmt *stmt)
 	DefElem    *as_item = NULL;
 	DefElem    *language_item = NULL;
 	char	   *language;
-	char	   *languageName;
 	Oid			laninline;
 	HeapTuple	languageTuple;
 	Form_pg_language languageStruct;
@@ -2008,16 +2003,13 @@ ExecuteDoStmt(DoStmt *stmt)
 	else
 		language = "plpgsql";
 
-	/* Convert language name to canonical case */
-	languageName = case_translate_language_name(language);
-
 	/* Look up the language and validate permissions */
-	languageTuple = SearchSysCache1(LANGNAME, PointerGetDatum(languageName));
+	languageTuple = SearchSysCache1(LANGNAME, PointerGetDatum(language));
 	if (!HeapTupleIsValid(languageTuple))
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("language \"%s\" does not exist", languageName),
+				 errmsg("language \"%s\" does not exist", language),
-				 (PLTemplateExists(languageName) ?
+				 (PLTemplateExists(language) ?
 				  errhint("Use CREATE LANGUAGE to load the language into the database.") : 0)));
 
 	codeblock->langOid = HeapTupleGetOid(languageTuple);

src/backend/commands/proclang.c

@@ -64,7 +64,6 @@ static void AlterLanguageOwner_internal(HeapTuple tup, Relation rel,
 void
 CreateProceduralLanguage(CreatePLangStmt *stmt)
 {
-	char	   *languageName;
 	PLTemplate *pltemplate;
 	Oid			handlerOid,
 				inlineOid,
@@ -72,16 +71,11 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	Oid			funcrettype;
 	Oid			funcargtypes[1];
 
-	/*
-	 * Translate the language name to lower case
-	 */
-	languageName = case_translate_language_name(stmt->plname);
-
 	/*
 	 * If we have template information for the language, ignore the supplied
 	 * parameters (if any) and use the template information.
 	 */
-	if ((pltemplate = find_language_template(languageName)) != NULL)
+	if ((pltemplate = find_language_template(stmt->plname)) != NULL)
 	{
 		List	   *funcname;
 
@@ -101,7 +95,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 				ereport(ERROR,
 						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 						 errmsg("must be superuser to create procedural language \"%s\"",
-								languageName)));
+								stmt->plname)));
 			if (!pg_database_ownercheck(MyDatabaseId, GetUserId()))
 				aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_DATABASE,
 							   get_database_name(MyDatabaseId));
@@ -226,7 +220,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 			valOid = InvalidOid;
 
 		/* ok, create it */
-		create_proc_lang(languageName, stmt->replace, GetUserId(),
+		create_proc_lang(stmt->plname, stmt->replace, GetUserId(),
 						 handlerOid, inlineOid,
 						 valOid, pltemplate->tmpltrusted);
 	}
@@ -241,7 +235,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_OBJECT),
 					 errmsg("unsupported language \"%s\"",
-							languageName),
+							stmt->plname),
 					 errhint("The supported languages are listed in the pg_pltemplate system catalog.")));
 
 		/*
@@ -301,7 +295,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 			valOid = InvalidOid;
 
 		/* ok, create it */
-		create_proc_lang(languageName, stmt->replace, GetUserId(),
+		create_proc_lang(stmt->plname, stmt->replace, GetUserId(),
 						 handlerOid, inlineOid,
 						 valOid, stmt->pltrusted);
 	}
@@ -521,21 +515,15 @@ PLTemplateExists(const char *languageName)
 void
 DropProceduralLanguage(DropPLangStmt *stmt)
 {
-	char	   *languageName;
 	Oid			oid;
 	ObjectAddress object;
 
-	/*
+	oid = get_language_oid(stmt->plname, stmt->missing_ok);
-	 * Translate the language name, check that the language exists
-	 */
-	languageName = case_translate_language_name(stmt->plname);
-
-	oid = get_language_oid(languageName, stmt->missing_ok);
 	if (!OidIsValid(oid))
 	{
 		ereport(NOTICE,
 				(errmsg("language \"%s\" does not exist, skipping",
-						languageName)));
+						stmt->plname)));
 		return;
 	}
 
@@ -544,7 +532,7 @@ DropProceduralLanguage(DropPLangStmt *stmt)
 	 */
 	if (!pg_language_ownercheck(oid, GetUserId()))
 		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_LANGUAGE,
-					   languageName);
+					   stmt->plname);
 
 	object.classId = LanguageRelationId;
 	object.objectId = oid;
@@ -587,10 +575,6 @@ RenameLanguage(const char *oldname, const char *newname)
 	HeapTuple	tup;
 	Relation	rel;
 
-	/* Translate both names for consistency with CREATE */
-	oldname = case_translate_language_name(oldname);
-	newname = case_translate_language_name(newname);
-
 	rel = heap_open(LanguageRelationId, RowExclusiveLock);
 
 	tup = SearchSysCacheCopy1(LANGNAME, CStringGetDatum(oldname));
@@ -628,9 +612,6 @@ AlterLanguageOwner(const char *name, Oid newOwnerId)
 	HeapTuple	tup;
 	Relation	rel;
 
-	/* Translate name for consistency with CREATE */
-	name = case_translate_language_name(name);
-
 	rel = heap_open(LanguageRelationId, RowExclusiveLock);
 
 	tup = SearchSysCache1(LANGNAME, CStringGetDatum(name));

src/include/commands/defrem.h

@@ -174,8 +174,6 @@ extern Datum transformGenericOptions(Oid catalogId,
 
 /* support routines in commands/define.c */
 
-extern char *case_translate_language_name(const char *input);
-
 extern char *defGetString(DefElem *def);
 extern double defGetNumeric(DefElem *def);
 extern bool defGetBoolean(DefElem *def);