DBA在一些场合下,要对无效的数据库对象进行重新编译.如果只是对all_objects等视图中选出来的无效对象进行重新编译,可能需要很多次:因为各个对象之间有依赖性的.这样并不是一个很好的办法.Raymond 在Recompiling invalid objects提到了如何有效地重新编译无效对象.提到了三种比较有效地方法(

• 利 用$ORACLE_HOME/rdbms/admin下的utlrp.sql脚本编译.一般都是在迁移或者升级之后运行该脚本.Raymond说该方法的 不足之处在于这个脚本是对整个数据库中的对象进行重新编译的,所以不可取.有网友指出utlrp.sql 实际上是调用utlrcmp.sql的这样就可以用utl_recomp包来做喽(这样就是比较好的方法).
• 用DBMS_UTILITY包来进行编译.但是也有一定的局限性.
• Raymond 提到了自己的解决办法: 不过也立刻有人指出来,这样对 View 的重新编译是无能为力的(ALTER_COMPILE只能处理:PACKAGE, PACKAGE BODY, PROCEDURE, FUNCTION, TRIGGER).参见下面的脚本

CREATE OR REPLACE PROCEDURE RECOMPILE_SCHEMA
IS
  v_Type USER_OBJECTS.OBJECT_TYPE%TYPE;
  v_Name USER_OBJECTS.OBJECT_NAME%TYPE;
  v_Stat USER_OBJECTS.STATUS%TYPE;

  CURSOR c_Obj
  IS
    SELECT  BASE
    FROM  (SELECT A.OBJECT_ID BASE
           ,      B.OBJECT_ID REL
           FROM   USER_OBJECTS A
              ,      USER_OBJECTS B
              ,      SYS.DEPENDENCY$  C
           WHERE  A.OBJECT_ID = C.D_OBJ#
           AND    B.OBJECT_ID = C.P_OBJ#
           AND    A.OBJECT_TYPE IN ('PACKAGE',
                                    'PROCEDURE',
                                    'FUNCTION',
                                    'PACKAGE BODY',
                                  --  'VIEW', 
                                    'TRIGGER')
           AND    B.OBJECT_TYPE IN ('PACKAGE',
                                    'PROCEDURE',
                                    'FUNCTION',
                                    'PACKAGE BODY',
                                  --  'VIEW', 
                                    'TRIGGER')
            AND    NOT A.OBJECT_NAME = B.OBJECT_NAME) OBJECTS
    CONNECT BY BASE = PRIOR REL
    GROUP   BY BASE
    ORDER   BY MAX(LEVEL) DESC;
BEGIN
  -- loop through all objects in order of dependancy.
  FOR c_Row IN c_Obj
  LOOP
    -- select the objects attributes (type, name & status).
    SELECT OBJECT_TYPE
    ,      OBJECT_NAME
    ,      STATUS
    INTO   v_Type
    ,      v_Name
    ,      v_Stat
    FROM   USER_OBJECTS
    WHERE  OBJECT_ID = c_Row.BASE;

    -- if the OBJECT is INVALID, recompile it.
    IF v_Stat = 'INVALID' THEN
      DBMS_DDL.ALTER_COMPILE(v_Type, USER, v_Name);
    END IF;
  END LOOP;

  -- Recompile all remaining INVALID OBJECTS (all those without dependencies).
  FOR c_Row IN ( SELECT OBJECT_TYPE
             ,      OBJECT_NAME
             FROM   USER_OBJECTS
             WHERE  STATUS = 'INVALID'
             AND    OBJECT_TYPE IN ('PACKAGE',
                                    'PROCEDURE',
                                    'FUNCTION',
                                    'TRIGGER',
                                    'PACKAGE BODY',
                                 --   'VIEW', 
                                    'TRIGGER') )
  LOOP
    DBMS_DDL.ALTER_COMPILE(c_Row.OBJECT_TYPE, USER, c_Row.OBJECT_NAME);
  END LOOP;
END RECOMPILE_SCHEMA;

Rem   EXAMPLES
Rem      1. Recompile all objects sequentially:
Rem             execute utl_recomp.recomp_serial();
Rem
Rem      2. Recompile objects in schema SCOTT sequentially:
Rem             execute utl_recomp.recomp_serial('SCOTT');
Rem
Rem      3. Recompile all objects using 4 parallel threads:
Rem             execute utl_recomp.recomp_parallel(4);
Rem
Rem      4. Recompile objects in schema JOE using the number of threads
Rem         specified in the paramter JOB_QUEUE_PROCESSES:
Rem             execute utl_recomp.recomp_parallel(NULL, 'JOE');
Rem
Rem      5. Recompile all objects using 2 parallel threads, but allow
Rem         other applications to use the job queue concurrently:
Rem             execute utl_recomp.recomp_parallel(2, NULL,
Rem                                                utl_recomp.share_job_queue);
Rem
Rem      6. Restore the job queue after a failure in recomp_parallel:
Rem             execute utl_recomp.restore_job_queue();