Index: src/backend/utils/adt/oracle_compat.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/oracle_compat.c,v
retrieving revision 1.57
diff -c -c -r1.57 oracle_compat.c
*** src/backend/utils/adt/oracle_compat.c	31 Dec 2004 22:01:22 -0000	1.57
--- src/backend/utils/adt/oracle_compat.c	15 Mar 2005 05:24:11 -0000
***************
*** 166,173 ****
  lower(PG_FUNCTION_ARGS)
  {
  #ifdef USE_WIDE_UPPER_LOWER
! 	/* use wide char code only when max encoding length > one */
! 	if (pg_database_encoding_max_length() > 1)
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
--- 166,173 ----
  lower(PG_FUNCTION_ARGS)
  {
  #ifdef USE_WIDE_UPPER_LOWER
! 	/* use wide char code only when max encoding length > 1 */
! 	if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
***************
*** 229,235 ****
  {
  #ifdef USE_WIDE_UPPER_LOWER
  	/* use wide char code only when max encoding length > one */
! 	if (pg_database_encoding_max_length() > 1)
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
--- 229,235 ----
  {
  #ifdef USE_WIDE_UPPER_LOWER
  	/* use wide char code only when max encoding length > one */
! 	if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
***************
*** 294,300 ****
  {
  #ifdef USE_WIDE_UPPER_LOWER
  	/* use wide char code only when max encoding length > one */
! 	if (pg_database_encoding_max_length() > 1)
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
--- 294,300 ----
  {
  #ifdef USE_WIDE_UPPER_LOWER
  	/* use wide char code only when max encoding length > one */
! 	if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
  	{
  		text	   *string = PG_GETARG_TEXT_P(0);
  		text	   *result;
Index: src/backend/utils/adt/pg_locale.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/pg_locale.c,v
retrieving revision 1.30
diff -c -c -r1.30 pg_locale.c
*** src/backend/utils/adt/pg_locale.c	1 Jan 2005 05:43:07 -0000	1.30
--- src/backend/utils/adt/pg_locale.c	15 Mar 2005 05:24:11 -0000
***************
*** 197,202 ****
--- 197,229 ----
  
  
  /*
+  * We'd like to cache whether LC_CTYPE is C (or POSIX), so we can
+  * optimize a few code paths in various places.
+  */
+ bool
+ lc_ctype_is_c(void)
+ {
+ 	/* Cache result so we only have to compute it once */
+ 	static int	result = -1;
+ 	char	   *localeptr;
+ 
+ 	if (result >= 0)
+ 		return (bool) result;
+ 	localeptr = setlocale(LC_CTYPE, NULL);
+ 	if (!localeptr)
+ 		elog(ERROR, "invalid LC_CTYPE setting");
+ 
+ 	if (strcmp(localeptr, "C") == 0)
+ 		result = true;
+ 	else if (strcmp(localeptr, "POSIX") == 0)
+ 		result = true;
+ 	else
+ 		result = false;
+ 	return (bool) result;
+ }
+ 
+ 
+ /*
   * Frees the malloced content of a struct lconv.  (But not the struct
   * itself.)
   */
Index: src/include/utils/pg_locale.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/utils/pg_locale.h,v
retrieving revision 1.19
diff -c -c -r1.19 pg_locale.h
*** src/include/utils/pg_locale.h	1 Jan 2005 05:43:09 -0000	1.19
--- src/include/utils/pg_locale.h	15 Mar 2005 05:24:16 -0000
***************
*** 32,37 ****
--- 32,38 ----
  				   bool doit, GucSource source);
  
  extern bool lc_collate_is_c(void);
+ extern bool lc_ctype_is_c(void);
  
  /*
   * Return the POSIX lconv struct (contains number/money formatting