clob变量值无法使用v$sql_bind_capture取得

clob情况：SQL> variable test_c clob;SQL> exec :test_c := 'test';PL/SQL procedure successfully completed.SQL> select * from test_clob where dbms_lob.substr(name,4000)=dbms_lob.substr(:test_c,4000);NAME--------------------------------------------------------------------------------testSQL> select sql_id,sql_text from v$sql where sql_text like 'select * from test_clob%';65v08jhcjtuunselect * from test_clob where dbms_lob.substr(name,4000)=dbms_lob.substr(:test_c,4000)SQL> select value_string from v$sql_bind_capture where sql_id='65v08jhcjtuun';VALUE_STRING