oracle重新编译失效对像

重新编译失效对像可执行utlrp.sql文件：

SQL> @?/rdbms/admin/utlrp.sql

TIMESTAMP
--------------------------------------------------------------------------------
COMP_TIMESTAMP UTLRP_BGN  2016-08-24 13:04:49

DOC>   The following PL/SQL block invokes UTL_RECOMP to recompile invalid
DOC>   objects in the database. Recompilation time is proportional to the
DOC>   number of invalid objects in the database, so this command may take
DOC>   a long time to execute on a database with a large number of invalid
DOC>   objects.
DOC>
DOC>   Use the following queries to track recompilation progress:
DOC>
DOC>   1. Query returning the number of invalid objects remaining. This
DOC>      number should decrease with time.
DOC>         SELECT COUNT(*) FROM obj$ WHERE status IN (4, 5, 6);
DOC>
DOC>   2. Query returning the number of objects compiled so far. This number
DOC>      should increase with time.
DOC>         SELECT COUNT(*) FROM UTL_RECOMP_COMPILED;
DOC>
DOC>   This script automatically chooses serial or parallel recompilation
DOC>   based on the number of CPUs available (parameter cpu_count) multiplied
DOC>   by the number of threads per CPU (parameter parallel_threads_per_cpu).
DOC>   On RAC, this number is added across all RAC nodes.
DOC>
DOC>   UTL_RECOMP uses DBMS_SCHEDULER to create jobs for parallel
DOC>   recompilation. Jobs are created without instance affinity so that they
DOC>   can migrate across RAC nodes. Use the following queries to verify
DOC>   whether UTL_RECOMP jobs are being created and run correctly:
DOC>
DOC>   1. Query showing jobs created by UTL_RECOMP
DOC>         SELECT job_name FROM dba_scheduler_jobs
DOC>            WHERE job_name like 'UTL_RECOMP_SLAVE_%';
DOC>
DOC>   2. Query showing UTL_RECOMP jobs that are running
DOC>         SELECT job_name FROM dba_scheduler_running_jobs
DOC>            WHERE job_name like 'UTL_RECOMP_SLAVE_%';
DOC>#

PL/SQL 过程已成功完成。

TIMESTAMP
--------------------------------------------------------------------------------
COMP_TIMESTAMP UTLRP_END  2016-08-24 13:04:50

PL/SQL 过程已成功完成。

DOC> The following query reports the number of objects that have compiled
DOC> with errors (objects that compile with errors have status set to 3 in
DOC> obj$). If the number is higher than expected, please examine the error
DOC> messages reported with each object (using SHOW ERRORS) to see if they
DOC> point to system misconfiguration or resource constraints that must be
DOC> fixed before attempting to recompile these objects.
DOC>#

OBJECTS WITH ERRORS
-------------------
                  4

DOC> The following query reports the number of errors caught during
DOC> recompilation. If this number is non-zero, please query the error
DOC> messages in the table UTL_RECOMP_ERRORS to see if any of these errors
DOC> are due to misconfiguration or resource constraints that must be
DOC> fixed before objects can compile successfully.
DOC>#

ERRORS DURING RECOMPILATION
---------------------------
                          0

PL/SQL 过程已成功完成。

进一步研究文件sql文件，可以看到，在默认情况下Oracle会调用存储过程utl_recomp.recomp_parallel并行编译无效包：

begin
  sys.UTL_RECOMP.recomp_parallel(0);
end;

当threads取值为0时，由Oracle根据参数cpu_count和parallel_threads_per_cpu自行决定并行度;

SQL> show parameter cpu

NAME                                 TYPE        VALUE
------------------------------------ ----------- --------------
cpu_count                            integer     4
parallel_threads_per_cpu             integer     2

有时候，由于Oracle bug 14065287，在启用并行编译无效对象时，脚本utlrp.sql会出现HANG现象，这时需要启用串行编译无效对象，如下所示：

BEGIN
   sys.utl_recomp.recomp_serial();
END;

注意：如果在执行中，中断了，下次如果再次执行时，有可能会出现名称已由现有对像使用,要在重编译前先删除下列索引

drop index SYS.UTL_RECOMP_COMP_IDX1;

使用并行执行时，会使用到SGA中的large pool,如果large pool大小不够大，会报如下错误：

ORA-12801: 并行查询服务器 P012 中发出错误信号
ORA-12853: PX 缓冲区的内存不足: 当前为 16336K, 最大需要 178560K
ORA-04031: 无法分配 65560 字节的共享内存 ("large pool","unknown object","large pool","PX msg pool")
ORA-06512: 在 "SYS.UTL_RECOMP", line 865
ORA-06512: 在 line 2

如果不是sys用户执行，可先授予相关的执行权限：

grant execute on UTL_RECOMP to XXX;