数据字典表Truncate丢失将招致数据库不可用

 泉源：赛迪网    作者：Arvin

在梦想的义务环境下，假如你在操作时将数据库内的几个数据字典表Truncate丢失，将会直接招致数据库不能再承袭使用，本文将针对一个相关案例举行详尽的讲解。

案例如下：

数据库环境：Oracle数据库9.2.0.7 RAC。（注：由于数据库的事故量体别年夜，以是数据库没有举行备份）。

反省后缔造的被截断表：

SQL> select object_name,object_type from dba_objects where object_name like 'IDL%';
OBJECT_NAME            OBJECT_TYPE
------------------- ------------------
IDL_CHAR$                 TABLE
IDL_SB4$                  TABLE
IDL_UB1$                  TABLE
IDL_UB2$                  TABLE

IDL_UB1$表是分外主要的字典表，只需出现妨碍，数据库就会出现年夜量的ORA-00600错误，全部事故将不能举行。

ORA-00600: internal error code, arguments: [17069],
[0xC0000000DDDFA690], [], [], [], [], [], []

ORA-600 17069错误是一个分外难明决的功效，功效出现后数据库的某个跟踪日记很快就会出现暴涨的环境，由于IDL系列字典表是记实数据库东西编译信息的，损失了此中的数据，全部进程、Package等都将无法执行。

字典表感化的阐明');：

IDL_UB1$ is one of four tables that hold compiled PL/SQL code:
IDL_UB1$
IDL_CHAR$
IDL_UB2$
IDL_SB4$
"PL/SQL is based on the programming language Ada. As a result, PL/SQL uses a
variant of Descriptive Intermediate Attributed Notation for Ada (DIANA), which
is a tree-structured intermediate language. It is defined using a meta-notation
called Interface Definition Language (IDL). DIANA provides for communication
internal to compilers and other tools.
"At compile time, PL/SQL source code is translated into machine-readable
m-code.Both the DIANA and m-code for a procedure or package are stored in the
database.At run time, they are loaded into the shared (memory) pool. The DIANA is
used to compile dependent procedures; the m-code is simply executed."
These four tables hold the DIANA and the so-code m-code. I think "m-code" is
short for machine-dependent byte code but there is a sizable machine-indenpendent part
as well. If you have a look at sql.bsq, you can see
that Oracle documents the "type" column of these tables as follows:
part number not null,
/* part: 0 = diana, 1 = portable pcode, 
2 = machine-dependentpcode */

假如出现更为严肃的环境，它将招致年夜量零碎DBMS包见效，其从新编译也将更为重大。

规单数据库，消除全部ORA-600错误的方式：

规复的方式是经过进程运转相关的剧本，重修和从新编译全部Procedure/Trigger/Package等东西，重重天生这些东西的DIANA和so-code m-code，首要包括catlog.sql,catproc.sql等剧本。

看重：即使以损耗年夜量的功夫为价格，一些ORA-00600错误也必须筹划。




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