作者：赵黎明，爱可生 MySQL DBA 团队成员，熟悉 Oracle、MySQL 等数据库，擅长数据库性能问题诊断、事务与锁问题的分析等，负责处理客户 MySQL 及我司自研 DMP 平台日常运维中的问题，对开源数据库相关技术非常感兴趣。
爱可生开源社区出品，原创内容未经授权不得随意使用，转载请联系小编并注明来源。
1背景
最近在客户这边遇到一个故障，在 Oracle 和 OB Oracle 租户下调用存储过程时，两者表现并不一致，导致获取到的 SQL 文本拼接不完整，影响到了业务侧的功能测试。
客户的存储过程逻辑并不复杂，就是通过查询系统视图 user_tab_columns 来获取用户的表名，然后再进行 SQL 拼接，完成后续的业务逻辑。
本文将针对这个问题进行相关的测试和验证。
2问题复现
Oracle 环境中验证
代码语言：javascript复制-- 创建测试用户并赋权
[root@localhost ~]# sqlplus / as sysdba
SQL> create user u1 identified by u1;
User created.
SQL> create user u2 identified by u2;
User created.
SQL> grant connect,resource to u1;
Grant succeeded.
SQL> grant create procedure to u1;
Grant succeeded.
SQL> grant connect,resource to u2;
Grant succeeded.
SQL> grant create synonym to u2;
Grant succeeded.
SQL> grant select any table to u2;
Grant succeeded.
-- 创建测试表并赋权
SQL> conn u1/u1
Connected.
SQL> create table t1(id int);
Table created.
SQL> insert into t1(id) values(1);
1 row created.
-- 创建表的同义词
SQL> conn u2/u2
Connected.
SQL> create synonym t1 for u1.t1;
Synonym created.
SQL> set lin 200
SQL> col owner for a5
SQL> col table_owner for a5
SQL> col db_link for a10
SQL> select * from all_synonyms where owner='U2';
OWNER SYNONYM_NAME TABLE TABLE_NAME DB_LINK
----- ------------------------------ ----- ------------------------------ ----------
U2 T1 U1 T1
-- 创建存储过程并赋权
SQL> conn u1/u1
Connected.
SQL> create or replace procedure proc_case1 as
v_str varchar2(10);
begin
select table_name into v_str from user_tab_columns where table_name='T1';
dbms_output.put_line(v_str);
end;
/ 2 3 4 5 6 7
Procedure created.
SQL> grant execute on proc_case1 to u2;
Grant succeeded.
-- 创建存储过程同义词
SQL> conn u2/u2
Connected.
SQL> create synonym proc_case1 for u1.proc_case1;
Synonym created.
SQL> select * from all_synonyms where owner='U2';
OWNER SYNONYM_NAME TABLE TABLE_NAME DB_LINK
----- ------------------------------ ----- ------------------------------ ----------
U2 PROC_CASE1 U1 PROC_CASE1
U2 T1 U1 T1
-- 验证
SQL> conn u1/u1
Connected.
SQL> select * from t1;
ID
----------
1
SQL> set serveroutput on;
SQL> call proc_case1();
T1
Call completed.
SQL> conn u2/u2
Connected.
SQL> select * from t1;
ID
----------
1
SQL> set serveroutput on;
SQL> call proc_case1();
T1
Call completed.
SQL>
由此可见，在 Oracle 中，无论是 u1 还是 u2 用户，调用存储过程时都能正确返回表名，说明两者查询 user_tab_columns 视图的返回结果是一致的，这也是符合预期的。
OB Oracle 环境中验证
代码语言：javascript复制-- 创建测试用户并赋权
SYS[SYS]> create user u1 identified by u1;
Query OK, 0 rows affected (0.04 sec)
SYS[SYS]> create user u2 identified by u2;
Query OK, 0 rows affected (0.04 sec)
SYS[SYS]> grant connect,resource to u1;
Query OK, 0 rows affected (0.04 sec)
SYS[SYS]> grant create procedure to u1;
Query OK, 0 rows affected (0.03 sec)
SYS[SYS]> grant connect,resource to u2;
Query OK, 0 rows affected (0.05 sec)
SYS[SYS]> grant create synonym to u2;
Query OK, 0 rows affected (0.03 sec)
SYS[SYS]> grant select any table to u2;
Query OK, 0 rows affected (0.03 sec)
-- 创建测试表并赋权
SYS[SYS]> conn u1
Connection id: 269006
Current database: U1
SYS[U1]> create table t1(id int);
Query OK, 0 rows affected (0.21 sec)
SYS[U1]> insert into t1(id) values(1);
Query OK, 1 row affected (0.03 sec)
SYS[U1]> commit;
Query OK, 0 rows affected (0.01 sec)
-- 创建表的同义词
SYS[U1]> conn u2
Connection id: 50837
Current database: U2
SYS[U2]> create synonym t1 for u1.t1;
Query OK, 0 rows affected (0.05 sec)
SYS[U2]> select * from all_synonyms where owner='U2';
------- -------------- ------------- ------------ ---------
| OWNER | SYNONYM_NAME | TABLE_OWNER | TABLE_NAME | DB_LINK |
------- -------------- ------------- ------------ ---------
| U2 | T1 | U1 | T1 | NULL |
------- -------------- ------------- ------------ ---------
2 rows in set (0.01 sec)
-- 创建存储过程并赋权
SYS[U2]> conn u1
Connection id: 269078
Current database: U1
SYS[U1]> create or replace procedure proc_case1 as
-> v_str varchar2(10);
-> begin
-> select table_name into v_str from user_tab_columns where table_name='T1';
-> dbms_output.put_line(v_str);
-> end;
-> /
Query OK, 0 rows affected (0.17 sec)
SYS[U1]> grant execute on proc_case1 to u2;
Query OK, 0 rows affected (0.06 sec)
-- 创建存储过程同义词
SYS[U1]> conn u2
Connection id: 50896
Current database: U2
SYS[U2]> create synonym proc_case1 for u1.proc_case1;
Query OK, 0 rows affected (0.05 sec)
SYS[U2]> select * from all_synonyms where owner='U2';
------- -------------- ------------- ------------ ---------
| OWNER | SYNONYM_NAME | TABLE_OWNER | TABLE_NAME | DB_LINK |
------- -------------- ------------- ------------ ---------
| U2 | PROC_CASE1 | U1 | PROC_CASE1 | NULL |
| U2 | T1 | U1 | T1 | NULL |
------- -------------- ------------- ------------ ---------
2 rows in set (0.01 sec)
-- 验证
SYS[U2]> conn u1
Connection id: 269134
Current database: U1
SYS[U1]> select * from t1;
------
| ID |
------
| 1 |
------
1 row in set (0.01sec)
SYS[U1]> set serveroutput on;
Query OK, 0 rows affected (0.41 sec)
SYS[U1]> call proc_case1();
Query OK, 0 rows affected (0.21 sec)
SYS[U1]> select table_name,column_name from user_tab_columns;
------------ -------------
| TABLE_NAME | COLUMN_NAME |
------------ -------------
| C | NAME |
| C | ADDRESS |
------------ -------------
2 rows in set (0.08 sec)
此处其实已经可以发现一些端倪，在 OB 中虽然可以通过 conn 进行用户切换，切换后的用户也能访问自己的对象，但是在访问 USER_ 等视图时，返回结果与 Oracle 不同。
用户 u1 查询 user_tab_columns 表时，只能看到 SYS 用户下的表（ C 表是由 SYS 用户创建的），所以存储过程无法返回 T1 表的表名，其查询结果为空。
-- 直连 u1 用户验证
U1[U1]> select * from t1;
------
| ID |
------
| 1 |
------
1 row in set (0.01sec)
U1[U1]> set serveroutput on;
Query OK, 0 rows affected (0.02sec)
U1[U1]> call proc_case1();
Query OK, 0 rows affected (0.08sec)
T1
U1[U1]>
-- 直连 u2 用户进行验证
U2[U2]> select * from t1;
------
| ID |
------
| 1 |
------
1 row in set (0.03sec)
U2[U2]> set serveroutput on;
Query OK, 0 rows affected (0.44 sec)
U2[U2]> call proc_case1();
Query OK, 0 rows affected (0.43 sec)
U2[U2]> select * from user_tab_columns;
Empty set (0.08 sec)
# 同样地，u2 也无法从 user_tab_columns 视图中查询到 u1 创建的表，调用存储过程返回结果为空
-- 将 user_tab_columns 替换成 all_tab_columns 视图
U2[U2]> select table_name,column_name from all_tab_columns where owner='U1';
------------ -------------
| TABLE_NAME | COLUMN_NAME |
------------ -------------
| T1 | ID |
------------ -------------
1 row in set (0.08 sec)
U2[U2]> create or replace procedure proc_case2 as
-> v_str varchar2(10);
-> begin
-> select table_name into v_str from all_tab_columns where table_name='T1' and owner='U1';
-> dbms_output.put_line(v_str);
-> end;
-> /
Query OK, 0 rows affected (0.17ec)
U2[U2]> call proc_case2();
Query OK, 0 rows affected (0.16ec)
T1
U2[U2]>
-- 将 SELECT ANY TABLE 权限回收
SYS[SYS]> revoke select any table from u2;
Query OK, 0 rows affected (0.03 sec)
U2[U2]> select table_name,column_name from all_tab_columns where owner='U1';
Empty set (0.05 sec)
U2[U2]> set serveroutput on;
Query OK, 0 rows affected (0.01 sec)
U2[U2]> call proc_case2();
Query OK, 0 rows affected (0.05 sec)
当用户 u2 没有 SELECT ANY TABLE 系统权限后，即使查询 all_tab_columns 视图，也无法获取其他用户创建表的相关信息。
3排查调用系统视图的相关对象
PL 对象
PL 对象，如：函数，存储过程等。
代码语言：javascript复制
-- dba_source 视图中存放了各种 PL 对象的定义
SQL> select count(*),type from dba_source group by type;
COUNT(*) TYPE
---------- ------------
152202 PROCEDURE
89318 PACKAGE
31504 PACKAGE BODY
1276 TYPE BODY
2210 TRIGGER
3895 FUNCTION
7 JAVA SOURCE
12338 TYPE
8 rows selected.
-- 创建测试存储过程（大小写各1个）
SQL> CREATE OR REPLACE PROCEDURE PROC_1 IS
V_N NUMBER :=0;
BEGIN
SELECT COUNT(*) INTO V_N FROM USER_TAB_COLUMNS;
END;
/ 2 3 4 5 6
Procedure created.
SQL> create or replace procedure proc_2 is
v_n number :=0;
begin
select count(*) into v_n from user_tab_columns;
end;
/ 2 3 4 5 6
Procedure created.
-- 查询常用系统视图名（此处只列举了几个与表相关的视图）
select owner,object_name,object_type from dba_objects where owner='SYS' and (object_name like 'USER_PART_%' or object_name like 'USER_T%' or object_name like 'ALL_PART_%' or object_name like 'ALL_T%' or object_name like 'DBA_PART_%' or object_name like 'DBA_T%');
-- 根据上一步获取到的系统视图名，通过模糊搜索，即可捕获到涉及查询这些系统视图的 PL 对象
SQL> set line 200 pages 9999 long 999999
SQL> col owner for a10
SQL> col name for a30
SQL> col text for a80
SQL> select owner,name,type,text from dba_source where owner not in('SYS', 'SYSTEM', 'SYSMAN', 'OUTLN', 'DIP', 'TSMSYS', 'DBSNMP',
'ORACLE_OCM', 'WMSYS', 'EXFSYS', 'XDB', 'ANONYMOUS', 'ORDSYS',
'ORDPLUGINS', 'SI_INFORMTN_SCHEMA', 'MDSYS', 'MGMT_VIEW', 'PERFSTAT',
'DMSYS', 'CTXSYS', 'OLAPSYS', 'MDDATA', 'APPQOSSYS', 'XS$NULL',
'ORDDATA', 'SPATIAL_WFS_ADMIN_USR', 'SPATIAL_CSW_ADMIN_USR',
'OWBSYS', 'APEX_PUBLIC_USER', 'APEX_030200', 'FLOWS_FILES', 'SCOTT',
'OMS', 'OWBSYS_AUDIT', 'DSG', 'DBMGR', 'PATROL', 'SPA', 'GOLDENGATE',
'DBADM') and owner not like 'MYNET%' and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%'); 2 3 4 5 6 7 8
OWNER NAME TYPE TEXT
---------- ------------------------------ ------------ --------------------------------------------------------------------------------
U1 PROC_CASE1 PROCEDURE select table_name into v_str from user_tab_columns where table_name='T1';
ZLM PROC_1 PROCEDURE SELECT COUNT(*) INTO V_N FROM USER_TAB_COLUMNS;
ZLM PROC_2 PROCEDURE select count(*) into v_n from user_tab_columns;
视图对象
代码语言：javascript复制
-- 创建测试视图1
SQL> create view view_1 as select * from user_tables;
View created.
-- 查询 dba_views 获取视图定义
SQL> select owner,view_name,text from dba_views where owner not in('SYS', 'SYSTEM', 'SYSMAN', 'OUTLN', 'DIP', 'TSMSYS', 'DBSNMP',
'ORACLE_OCM', 'WMSYS', 'EXFSYS', 'XDB', 'ANONYMOUS', 'ORDSYS',
'ORDPLUGINS', 'SI_INFORMTN_SCHEMA', 'MDSYS', 'MGMT_VIEW', 'PERFSTAT',
'DMSYS', 'CTXSYS', 'OLAPSYS', 'MDDATA', 'APPQOSSYS', 'XS$NULL',
'ORDDATA', 'SPATIAL_WFS_ADMIN_USR', 'SPATIAL_CSW_ADMIN_USR',
'OWBSYS', 'APEX_PUBLIC_USER', 'APEX_030200', 'FLOWS_FILES', 'SCOTT',
'OMS', 'OWBSYS_AUDIT', 'DSG', 'DBMGR', 'PATROL', 'SPA', 'GOLDENGATE',
'DBADM') and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%');
2 3 4 5 6 7 8 'DBADM') and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%')
*
ERROR at line 8:
ORA-00932: inconsistent datatypes: expected NUMBER got LONG
dba_source视图中的 text 列是 varchar2 类型的，可以直接使用 like 进行模糊查询。dba_views视图中的 text 列是 long 类型的，无法直接使用 like 进行模糊查询，会报 ORA-00932 的错误。
workaround：先创建一张表，用 to_lob 函数将 text 字段转换为 clob 类型，然后将 dba_views 拷贝到该表中，再通过以上 SQL 进行查询。
-- 创建中间表并将系统视图 dba_views 内容拷贝到该表
SQL> create table my_views as select owner,view_name,to_lob(text) text from dba_views;
Table created.
-- 查询中间表捕获目标视图对象
SQL> select owner,view_name,text from my_views where owner not in('SYS', 'SYSTEM', 'SYSMAN', 'OUTLN', 'DIP', 'TSMSYS', 'DBSNMP', 'ORACLE_OCM', 'WMSYS', 'EXFSYS', 'XDB', 'ANONYMOUS', 'ORDSYS', 'ORDPLUGINS', 'SI_INFORMTN_SCHEMA', 'MDSYS', 'MGMT_VIEW', 'PERFSTAT', 'DMSYS', 'CTXSYS', 'OLAPSYS', 'MDDATA', 'APPQOSSYS', 'XS$NULL', 'ORDDATA', 'SPATIAL_WFS_ADMIN_USR', 'SPATIAL_CSW_ADMIN_USR', 'OWBSYS', 'APEX_PUBLIC_USER', 'APEX_030200', 'FLOWS_FILES', 'SCOTT', 'OMS', 'OWBSYS_AUDIT', 'DSG', 'DBMGR', 'PATROL', 'SPA', 'GOLDENGATE', 'DBADM') and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%'); 2 3 4 5 6 7 8
OWNER VIEW_NAME TEXT---------- ------------------------------ --------------------------------------------------------------------------------
ZLM VIEW_1 select "TABLE_NAME","TABLESPACE_NAME","CLUSTER_NAME","IOT_NAME","STATUS","PCT_FR EE","PCT_USED","INI_TRANS","MAX_TRANS","INITIAL_EXTENT","NEXT_EXTENT","MIN_EXTEN TS","MAX_EXTENTS","PCT_INCREASE","FREELISTS","FREELIST_GROUPS","LOGGING","BACKED _UP","NUM_ROWS","BLOCKS","EMPTY_BLOCKS","AVG_SPACE","CHAIN_CNT","AVG_ROW_LEN","A VG_SPACE_FREELIST_BLOCKS","NUM_FREELIST_BLOCKS","DEGREE","INSTANCES","CACHE","TA BLE_LOCK","SAMPLE_SIZE","LAST_ANALYZED","PARTITIONED","IOT_TYPE","TEMPORARY","SE CONDARY","NESTED","BUFFER_POOL","ROW_MOVEMENT","GLOBAL_STATS","USER_STATS","DURA TION","SKIP_CORRUPT","MONITORING","CLUSTER_OWNER","DEPENDENCIES","COMPRESSION"," DROPPED" from user_tables
该方法可以满足需求，但每次有新的视图被创建时，需要 drop 并重建表，比较繁琐。
workaround：创建物化视图来代替中间表。
代码语言：javascript复制-- 创建物化视图
SQL> create materialized view my_mviews
refresh force
on demand
start with sysdate
next sysdate 10 /(24*60)
as
select owner,view_name,to_lob(text) text from dba_views; 2 3 4 5 6 7
Materialized view created.
-- 创建测试视图2
SQL> CREATE VIEW VIEW_2 AS SELECT * FROM USER_TABLES;
View created.
-- 查看是否捕获到 view_2 视图
SQL> select owner,view_name,text from my_mviews where owner not in('SYS', 'SYSTEM', 'SYSMAN', 'OUTLN', 'DIP', 'TSMSYS', 'DBSNMP',
'ORACLE_OCM', 'WMSYS', 'EXFSYS', 'XDB', 'ANONYMOUS', 'ORDSYS',
'ORDPLUGINS', 'SI_INFORMTN_SCHEMA', 'MDSYS', 'MGMT_VIEW', 'PERFSTAT',
'DMSYS', 'CTXSYS', 'OLAPSYS', 'MDDATA', 'APPQOSSYS', 'XS$NULL',
'ORDDATA', 'SPATIAL_WFS_ADMIN_USR', 'SPATIAL_CSW_ADMIN_USR',
'OWBSYS', 'APEX_PUBLIC_USER', 'APEX_030200', 'FLOWS_FILES', 'SCOTT',
'OMS', 'OWBSYS_AUDIT', 'DSG', 'DBMGR', 'PATROL', 'SPA', 'GOLDENGATE',
'DBADM') and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%'); 2 3 4 5 6 7 8
OWNER VIEW_NAME TEXT
---------- ------------------------------ --------------------------------------------------------------------------------
ZLM VIEW_1 select "TABLE_NAME","TABLESPACE_NAME","CLUSTER_NAME","IOT_NAME","STATUS","PCT_FR
EE","PCT_USED","INI_TRANS","MAX_TRANS","INITIAL_EXTENT","NEXT_EXTENT","MIN_EXTEN
TS","MAX_EXTENTS","PCT_INCREASE","FREELISTS","FREELIST_GROUPS","LOGGING","BACKED
_UP","NUM_ROWS","BLOCKS","EMPTY_BLOCKS","AVG_SPACE","CHAIN_CNT","AVG_ROW_LEN","A
VG_SPACE_FREELIST_BLOCKS","NUM_FREELIST_BLOCKS","DEGREE","INSTANCES","CACHE","TA
BLE_LOCK","SAMPLE_SIZE","LAST_ANALYZED","PARTITIONED","IOT_TYPE","TEMPORARY","SE
CONDARY","NESTED","BUFFER_POOL","ROW_MOVEMENT","GLOBAL_STATS","USER_STATS","DURA
TION","SKIP_CORRUPT","MONITORING","CLUSTER_OWNER","DEPENDENCIES","COMPRESSION","
DROPPED" from user_tables
-- 查看物化视图刷新时间
SQL> select owner,mview_name,last_refresh_type,last_refresh_date from user_mviews;
OWNER MVIEW_NAME LAST_REF LAST_REFRESH_DATE
---------- ------------------------------ -------- -------------------
ZLM MY_MVIEWS COMPLETE 2023-08-03 16:07:15
-- 手动刷新物化视图
SQL> exec dbms_mview.refresh('my_mviews');
PL/SQL procedure successfully completed.
SQL> select owner,mview_name,last_refresh_type,last_refresh_date from user_mviews;
OWNER MVIEW_NAME LAST_REF LAST_REFRESH_DATE
---------- ------------------------------ -------- -------------------
ZLM MY_MVIEWS COMPLETE 2023-08-03 16:21:45
-- 再次查询物化视图，此时 view_2 也能被捕获到了，这样就无需重复建表，当有新视图被创建的时候，只需手动刷新物化视图即可
SQL> select owner,view_name,text from my_mviews where owner not in('SYS', 'SYSTEM', 'SYSMAN', 'OUTLN', 'DIP', 'TSMSYS', 'DBSNMP',
'ORACLE_OCM', 'WMSYS', 'EXFSYS', 'XDB', 'ANONYMOUS', 'ORDSYS',
'ORDPLUGINS', 'SI_INFORMTN_SCHEMA', 'MDSYS', 'MGMT_VIEW', 'PERFSTAT',
'DMSYS', 'CTXSYS', 'OLAPSYS', 'MDDATA', 'APPQOSSYS', 'XS$NULL',
'ORDDATA', 'SPATIAL_WFS_ADMIN_USR', 'SPATIAL_CSW_ADMIN_USR',
'OWBSYS', 'APEX_PUBLIC_USER', 'APEX_030200', 'FLOWS_FILES', 'SCOTT',
'OMS', 'OWBSYS_AUDIT', 'DSG', 'DBMGR', 'PATROL', 'SPA', 'GOLDENGATE',
'DBADM') and (text like '%USER_TAB_COLUMNS%' or text like '%user_tab_columns%' or text like '%USER%TABLES%' or text like '%user%tables%' or text like '%ALL_TAB_COLUMNS%' or text like '%ALL_tab_columns%' or text like '%ALL%TABLES%' or text like '%ALL%tables%'); 2 3 4 5 6 7 8
OWNER VIEW_NAME TEXT
---------- ------------------------------ --------------------------------------------------------------------------------
ZLM VIEW_1 select "TABLE_NAME","TABLESPACE_NAME","CLUSTER_NAME","IOT_NAME","STATUS","PCT_FR
EE","PCT_USED","INI_TRANS","MAX_TRANS","INITIAL_EXTENT","NEXT_EXTENT","MIN_EXTEN
TS","MAX_EXTENTS","PCT_INCREASE","FREELISTS","FREELIST_GROUPS","LOGGING","BACKED
_UP","NUM_ROWS","BLOCKS","EMPTY_BLOCKS","AVG_SPACE","CHAIN_CNT","AVG_ROW_LEN","A
VG_SPACE_FREELIST_BLOCKS","NUM_FREELIST_BLOCKS","DEGREE","INSTANCES","CACHE","TA
BLE_LOCK","SAMPLE_SIZE","LAST_ANALYZED","PARTITIONED","IOT_TYPE","TEMPORARY","SE
CONDARY","NESTED","BUFFER_POOL","ROW_MOVEMENT","GLOBAL_STATS","USER_STATS","DURA
TION","SKIP_CORRUPT","MONITORING","CLUSTER_OWNER","DEPENDENCIES","COMPRESSION","
DROPPED" from user_tables
ZLM VIEW_2 select "TABLE_NAME","TABLESPACE_NAME","CLUSTER_NAME","IOT_NAME","STATUS","PCT_FR
EE","PCT_USED","INI_TRANS","MAX_TRANS","INITIAL_EXTENT","NEXT_EXTENT","MIN_EXTEN
TS","MAX_EXTENTS","PCT_INCREASE","FREELISTS","FREELIST_GROUPS","LOGGING","BACKED
_UP","NUM_ROWS","BLOCKS","EMPTY_BLOCKS","AVG_SPACE","CHAIN_CNT","AVG_ROW_LEN","A
VG_SPACE_FREELIST_BLOCKS","NUM_FREELIST_BLOCKS","DEGREE","INSTANCES","CACHE","TA
BLE_LOCK","SAMPLE_SIZE","LAST_ANALYZED","PARTITIONED","IOT_TYPE","TEMPORARY","SE
CONDARY","NESTED","BUFFER_POOL","ROW_MOVEMENT","GLOBAL_STATS","USER_STATS","DURA
TION","SKIP_CORRUPT","MONITORING","CLUSTER_OWNER","DEPENDENCIES","COMPRESSION","
DROPPED" from USER_TABLES
4解决方案
将存储过程中的 user_tab_columns 视图替换成 all_tab_columns，虽然可作为临时方案，不过存在以下缺点：
- 需要修改业务代码，即替换存储过程中查询相关系统视图的部分。
- 使用同义词来访问对象的用户，需要有 SELECT ANY TABLE 的系统权限，否则即便使用
all_开头的视图，也查询不到目标对象。 - 赋予执行用户 dba 权限，并修改原有查询 SQL，增加 owner='XXX' 的条件（存在安全隐患，不推荐）。
- OB 能提供一个 hotfix patch 来彻底解决该问题。
5问题总结
在 OB 中，普通用户查询 USER_TAB_COLUMNS 系统视图权限的逻辑与 Oracle 并不一致，导致查询结果有差异。
除了 USER_TAB_COLUMNS 视图，还有其他以 USER_ 开头的视图，也存在类似的问题，比如：USER_SYNONYMS、USER_TABLES 等。
对于系统中已有的对象，应尽快排查并确认在哪些对象中用到了这些系统视图，在该问题被彻底修复前，建议先对相关代码进行临时修改，使其能继续完成后续的功能验证。
本文关键字：#OceanBase# #Oracle# #视图#
