diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index d3565a5..d9ef10e 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -78,7 +78,8 @@ LETTER			[A-Za-z_\200-\377]
 LETTER_OR_DIGIT [A-Za-z_0-9\200-\377]
 
 ID				{LETTER}{LETTER_OR_DIGIT}*
-QUALIFIED_ID	{ID}"."{ID}
+SECONDARY_ID	{LETTER_OR_DIGIT}+
+QUALIFIED_ID	{ID}("."{SECONDARY_ID})+
 
 UNQUOTED_STRING {LETTER}({LETTER_OR_DIGIT}|[-._:/])*
 STRING			\'([^'\\\n]|\\.|\'\')*\'