ORA-04021: 等待锁定对象时发生超时

Question

我有这个匿名 PL/SQL 块，它从 table.

计算并打印值 return

DECLARE
    U_ID NUMBER :=39;
    RETAIL BINARY_FLOAT:=1;
    FLAG NUMBER;
BEGIN
    SELECT NVL(RETAIL_AMOUNT,1),UNIT_ID INTO RETAIL, FLAG FROM UNITS WHERE UNIT_ID=U_ID;
    LOOP
    SELECT NVL(MAX(UNIT_ID),U_ID) INTO FLAG FROM  UNITS WHERE FATHER_ID=FLAG;
    IF FLAG=U_ID THEN EXIT; END IF;
    SELECT RETAIL* RETAIL_AMOUNT INTO RETAIL FROM UNITS WHERE UNIT_ID=FLAG;
    EXIT WHEN FLAG=U_ID;
    END LOOP;
DBMS_OUTPUT.PUT_LINE( RETAIL);
END;

这个块工作正常，但我想用 PL/SQL 函数做同样的事情

我写的函数如下：

CREATE OR REPLACE FUNCTION GET_UNIT_RETAIL(U_ID NUMBER)
     RETURN NUMBER
IS
    RETAIL BINARY_FLOAT:=1;
    FLAG NUMBER;
BEGIN
    SELECT NVL(RETAIL_AMOUNT,1),UNIT_ID 
    INTO RETAIL, FLAG 
    FROM UNITS 
    WHERE UNIT_ID=U_ID;

    LOOP
        SELECT NVL(MAX(UNIT_ID),U_ID) 
        INTO FLAG 
        FROM  UNITS 
        WHERE FATHER_ID=FLAG;
        IF FLAG=U_ID THEN 
            EXIT; 
        END IF;
        SELECT RETAIL* RETAIL_AMOUNT 
        INTO RETAIL 
        FROM UNITS 
        WHERE UNIT_ID=FLAG;
        EXIT WHEN FLAG=U_ID;
    END LOOP;

    RETURN NUMBER;
END;
/

当我尝试执行上面的代码将函数保存到数据库时，环境 (SQL*PLUS) 挂了很长时间，最后 returns 这个错误：

ERROR at line 1:
ORA-04021: timeout occurred while waiting to lock object

有什么问题吗？？？请!

Answer 1

听起来像 ddl_lock 问题

看看
dba_ddl_locks 看看谁是 "blocking" 创建或替换。

也尝试在 不同的名称 下创建 - 看看会发生什么。

Answer 2

问题是因为对象 GET_UNIT_RETAIL 正被其他环境占用答案如下：

https://community.oracle.com/thread/2321256

ORA-04021: 等待锁定对象时发生超时

ORA-04021: timeout occurred while waiting to lock object

oracle

plsql

sqlplus