模拟19c数据库root pdb undo异常恢复

联系:手机/微信(+86 13429648788) QQ(107644445)QQ咨询惜分飞

标题:模拟19c数据库root pdb undo异常恢复

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

对于19c在pdb情况下三种常见故障进行了模拟测试:
模拟19c数据库redo异常恢复
模拟19c数据库pdb undo异常恢复
模拟19c数据库root pdb undo异常恢复
模拟oracle 19c cdb模式下root pdb中undo丢失故障恢复
会话1,pdb中插入大量数据,未提交

SQL> alter session set container=pdb; 

Session altered.

SQL> alter database open;

Database altered.

SQL> create user xff identified by oracle default tablespace users;
grant dba to xff;
conn xff/oracle@127.0.0.1/pdb
create table t_xifenfei as select * from dba_objects;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;

User created.

SQL> 
Grant succeeded.

SQL> Connected.
SQL> 

Table created.

SQL> 
72351 rows created.

SQL> 
144702 rows created.

SQL> 
289404 rows created.

SQL> 
578808 rows created.

SQL> 

1157616 rows created.

SQL> SQL> SQL> 

会话2中root pdb模拟事务

[oracle@localhost ~]$ ss

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Nov 16 16:56:01 2020
Version 19.5.0.0.0

Copyright (c) 1982, 2019, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.5.0.0.0

SQL> 
SQL> 
SQL> conn system/oracle
Connected.
SQL> create table t_xifenfei tablespace users as select * from dba_objects;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;
insert into t_xifenfei select * from t_xifenfei;

Table created.

SQL> 
72380 rows created.

SQL> 
144760 rows created.

SQL> 
289520 rows created.

SQL> 
579040 rows created.

SQL> 

1158080 rows created.

SQL> SQL> 

会话3 abort库并删除root pdb中undo文件

[oracle@localhost ~]$ ss

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Nov 16 16:56:55 2020
Version 19.5.0.0.0

Copyright (c) 1982, 2019, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.5.0.0.0

SQL> shutdown abort;
ORACLE instance shut down.
SQL> 

[oracle@localhost oradata]$ cd ORA19C
[oracle@localhost ORA19C]$ ls
control01.ctl  control02.ctl  pdb  pdbseed  redo01.log  redo02.log  redo03.log  sysaux01.dbf
system01.dbf  temp01.dbf  undotbs01.dbf  users01.dbf
[oracle@localhost ORA19C]$ rm -rf undotbs01.dbf 

启动数据库报ORA-01157 ORA-01110错误

SQL> alter database datafile 4 offline drop;

Database altered.

SQL> alter database open;

Database altered.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB                            MOUNTED
SQL> alter session set container=pdb;

Session altered.

SQL> alter database open;

Database altered.

SQL> conn / as sysdba
Connected.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB                            READ WRITE NO
 
SQL> SQL> select tablespace_name,segment_name,status from dba_rollback_segs;

TABLESPACE_NAME                SEGMENT_NAME                   STATUS
------------------------------ ------------------------------ --------------------------------
SYSTEM                         SYSTEM                         ONLINE
UNDOTBS1                       _SYSSMU1_1261223759$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU2_27624015$             NEEDS RECOVERY
UNDOTBS1                       _SYSSMU3_2421748942$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU4_625702278$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU5_2101348960$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU6_813816332$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU7_2329891355$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU8_399776867$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU9_1692468413$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU10_930580995$           NEEDS RECOVERY

本次测试比较幸运,虽然undo段状态为NEEDS RECOVERY,但是数据库直接open成功.实际生产情况,可能比这个要复杂很多

模拟19c数据库pdb undo异常恢复

联系:手机/微信(+86 13429648788) QQ(107644445)QQ咨询惜分飞

标题:模拟19c数据库pdb undo异常恢复

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

对于19c在pdb情况下三种常见故障进行了模拟测试:
模拟19c数据库redo异常恢复
模拟19c数据库pdb undo异常恢复
模拟19c数据库root pdb undo异常恢复
测试在有事务的情况下,删除pdb中的undo数据库异常情况测试
会话1在root pdb中删除表记录,不提交

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB                            READ WRITE NO
SQL> delete from system.t_xifenfei;

2316160 rows deleted.

会话2在pdb中删除表记录,不提交

SQL> conn xff/oracle@127.0.0.1/pdb
Connected.
SQL> delete from xff.t_xifenfei;

72351 rows deleted.

会话3 直接abort库

SQL> shutdown abort;
ORACLE instance shut down.

删除pdb中undo文件

[oracle@localhost pdb]$ rm -rf undotbs01.dbf 
[oracle@localhost pdb]$ 

启动数据库

SQL> startup
ORACLE instance started.

Total System Global Area 4999609088 bytes
Fixed Size                  9145088 bytes
Variable Size             905969664 bytes
Database Buffers         4076863488 bytes
Redo Buffers                7630848 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 11 - see DBWR trace file
ORA-01110: data file 11: '/u01/app/oracle/oradata/ORA19C/pdb/undotbs01.dbf'

offline异常文件,再open库

SQL> alter database datafile 11 offline drop;
alter database datafile 11 offline drop
*
ERROR at line 1:
ORA-01516: nonexistent log file, data file, or temporary file "11" in the current container

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       MOUNTED
         3 PDB                            MOUNTED
SQL> alter session set container=pdb;

Session altered.

SQL> alter database datafile 11 offline drop;

Database altered.

SQL> conn / as sysdba
Connected.

SQL> startup 
ORACLE instance started.

Total System Global Area 4999609088 bytes
Fixed Size                  9145088 bytes
Variable Size             905969664 bytes
Database Buffers         4076863488 bytes
Redo Buffers                7630848 bytes
Database mounted.
Database opened.

open pdb

SQL> alter session set container=pdb;

Session altered.

SQL> 
SQL> alter database open;

Database altered.

SQL> conn / as sysdba
Connected.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB                            READ WRITE NO

测试中库open比较简单,后续只要对异常undo进行处理即可

SQL> create undo tablespace undotbs2 datafile '/u01/app/oracle/oradata/ORA19C/pdb/undotbs02.dbf' size 128M autoextend on;

Tablespace created.

SQL> alter system set undo_tablespace=undotbs2;

System altered.

SQL> select tablespace_name,segment_name,status from dba_rollback_segs;

TABLESPACE_NAME                SEGMENT_NAME                   STATUS
------------------------------ ------------------------------ --------------------------------
SYSTEM                         SYSTEM                         ONLINE
UNDOTBS1                       _SYSSMU1_3588498444$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU2_2971032042$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU3_3657342154$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU4_811969446$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU5_3018429039$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU6_442110264$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU7_2728255665$           NEEDS RECOVERY
UNDOTBS1                       _SYSSMU8_801938064$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU9_647420285$            NEEDS RECOVERY
UNDOTBS1                       _SYSSMU10_2262159254$          NEEDS RECOVERY

SQL>  drop tablespace undotbs1 including contents and datafiles;

Tablespace dropped.

在测试中,undo有事务的情况下,数据库可以正常open,而且运行了一段时间未crash,在这个方面确实比11g及其以前版本有很大改进.当然由于测试环境本身比较单一,可能实际生产中会此类故障处理比较复杂