模拟19c数据库root pdb undo异常恢复

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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

linux资源限制导致数据库异常

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

标题:linux资源限制导致数据库异常

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.]

一起由于liunx系统资源限制导致数据库无法启动案例分享
数据库启动报ORA-01157错

SQL> startup
ORACLE instance started.

Total System Global Area 3340451840 bytes
Fixed Size		    2217952 bytes
Variable Size		 1862273056 bytes
Database Buffers	 1459617792 bytes
Redo Buffers		   16343040 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 5 - see DBWR trace file
ORA-01110: data file 5: '/home/oracle/oradata/XIFENFEI.dbf'

该错误一般是由于文件丢失或者路径错误导致

alert日志显示

Sun Apr 07 20:57:03 2019
ALTER DATABASE OPEN
Sun Apr 07 20:57:03 2019
Errors in file /dbdata/oracle/diag/rdbms/orcl/orcl/trace/orcl_dbw0_2681.trc:
ORA-01157: cannot identify/lock data file 5 - see DBWR trace file
ORA-01110: data file 5: '/home/oracle/oradata/XIFENFEI.dbf'
ORA-27092: size of file exceeds file size limit of the process
Additional information: 262144
Additional information: 262145
Errors in file /dbdata/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_2802.trc:
ORA-01157: cannot identify/lock data file 5 - see DBWR trace file
ORA-01110: data file 5: '/home/oracle/oradata/XIFENFEI.dbf'
ORA-1157 signalled during: ALTER DATABASE OPEN...
Sun Apr 07 20:57:04 2019
Errors in file /dbdata/oracle/diag/rdbms/orcl/orcl/trace/orcl_m000_2804.trc  (incident=38578):
ORA-00600: internal error code, arguments: [kcidr_io_check_common_6], [10], 
     [/home/oracle/oradata/XIFENFEI.dbf], [8192], [2], [5], [], [], [], [], [], []
ORA-27092: size of file exceeds file size limit of the process

这里看到提示ORA-27092: size of file exceeds file size limit of the process
查看系统limit配置

[oracle@XFF ~]$ ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) 640000
scheduling priority             (-e) 0
file size               (blocks, -f) 2097152
pending signals                 (-i) 128489
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 131072
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 131072
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

一般操作系统block size为1k,这里限制文件大小为2097152=(2G)
查看文件

[oracle@XFF ~]$ ls -l /home/oracle/oradata/XIFENFEI.dbf
-rw-r-----. 1 oracle oinstall 2147491840 Apr  7 19:04 /home/oracle/oradata/XIFENFEI.dbf

文件大小为2097160>2097152,导致异常

设置系统对文件大小限制2097152kb

[root@XFF ~]# ulimit -f 102400000
[root@XFF ~]# su - oracle
[oracle@XFF ~]$ ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) 640000
scheduling priority             (-e) 0
file size               (blocks, -f) 102400000
pending signals                 (-i) 128489
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 131072
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 131072
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

重启数据库,open成功

SQL> shutdown immediate;      
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 3340451840 bytes
Fixed Size		    2217952 bytes
Variable Size		 1862273056 bytes
Database Buffers	 1459617792 bytes
Redo Buffers		   16343040 bytes
Database mounted.
Database opened.