diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index fc3c5b0..fdf58cf 100644
*** a/src/backend/utils/adt/selfuncs.c
--- b/src/backend/utils/adt/selfuncs.c
*************** make_greater_string(const Const *str_con
*** 5542,5552 ****
  		*lastchar = savelastchar;
  
  		/*
! 		 * Truncate off the last character, which might be more than 1 byte,
! 		 * depending on the character encoding.
  		 */
  		if (datatype != BYTEAOID && pg_database_encoding_max_length() > 1)
! 			len = pg_mbcliplen(workstr, len, len - 1);
  		else
  			len -= 1;
  
--- 5542,5567 ----
  		*lastchar = savelastchar;
  
  		/*
! 		 * Increment the previous character, or truncate off the last character,
! 		 * which might be more than 1 byte, depending on the character encoding.
  		 */
  		if (datatype != BYTEAOID && pg_database_encoding_max_length() > 1)
! 		{
! 			int		i;
! 			int		cliplen = pg_mbcliplen(workstr, len, len - 1);
! 
! 			for (i = len - 1; i > cliplen; i--)
! 			{
! 				if ((unsigned char) workstr[i] < (unsigned char) 255)
! 				{
! 					workstr[i]++;
! 					memset(workstr + i + 1, 1 /* or 0? */, len - i);
! 					break;
! 				}
! 			}
! 			if (i <= cliplen)
! 				len = cliplen;
! 		}
  		else
  			len -= 1;