diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 4ec57e11d33..206a1d1898a 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -680,6 +680,10 @@ show_session_authorization(void)
 	Oid			savedoid;
 	char	   *endptr;
 
+	/* If session_authorization hasn't been set in this process, return "" */
+	if (value == NULL || value[0] == '\0')
+		return "";
+
 	Assert(strspn(value, "x") == NAMEDATALEN &&
 		   (value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'));