2165.达梦数据库REDO误删除恢复疑问？
IT小Chen2024-05-13
42
说明:
在没有备份的情况下，经测试非CURRENT REDO LOG FILE丢失可以恢复，CURRENT REDO LOG FILE使用网上的方法无法恢复，初步怀疑新版本对REDO增加了更严格的校验，具体恢复方法还要咨询原厂，测试过程如下。
环境说明:
数据库版本
SQL> SELECT * FROM V$VERSION;
LINEID BANNER
1 DM Database Server 64 V8
2 DB Version: 0x7000c
3 03134284172-20240321-222308-20093
4 Msg Version: 0
5 Gsu level(3-4) cnt: 3
6 Gsu level(5) cnt: 0
小版本：
SQL> SELECT BUILD_VERSION FROM V$INSTANCE;
LINEID BUILD_VERSION
1 1-3-140-2024.03.21-222308-20093-ENT
补丁版本：
SQL> SELECT ID_CODE;
LINEID ID_CODE
1 --03134284172-20240321-222308-20093
安装介质下载地址
https://www.dameng.com/list_103.html
创建测试数据
SQL> CREATE TABLE T1(ID INT);
SQL> INSERT INTO T1 VALUES(1),(2),(3);
SQL> COMMIT;
查询信息
查看REDO信息
SQL> SELECT GROUP_ID,FILE_ID,PATH,RLOG_SIZE FROM V$RLOGFILE;
LINEID GROUP_ID FILE_ID PATH RLOG_SIZE
1 2 0 dm8/data/CJC/CJC01.log 268435456
2 2 1 dm8/data/CJC/CJC02.log 268435456
SQL> SELECT CKPT_LSN,FILE_LSN,FLUSH_LSN,CUR_LSN,DB_MAGIC FROM V$RLOG;
LINEID CKPT_LSN FILE_LSN FLUSH_LSN CUR_LSN DB_MAGIC
1 44644 44656 44656 44656 1516351486
新增数据
INSERT INTO T1 VALUES(4),(5);
COMMIT;
SQL> SELECT CKPT_LSN,FILE_LSN,FLUSH_LSN,CUR_LSN,DB_MAGIC FROM V$RLOG;
LINEID CKPT_LSN FILE_LSN FLUSH_LSN CUR_LSN DB_MAGIC
1 44644 44661 44661 44661 1516351486
VROG和VRLOGFILE视图说明：
https://eco.dameng.com/document/dm/zh-cn/pm/dm8-admin-manual-appendix#6.%20%E6%97%A5%E5%BF%97%E7%AE%A1%E7%90%86
V$RLOG
显示日志的总体信息。通过该视图可以了解系统当前日志事务号 LSN 的情况、归档日志情况、检查点的执行情况等。
…
V$RLOGFILE
显示日志文件的具体信息。包括文件号、完整路径、文件的状态、文件大小等等。
查看REDO信息
SQL> host ls -lrth dm8/data/CJC/CJC*.log
-rw-r–r-- 1 dmdba dinstall 256M May 11 21:45 dm8/data/CJC/CJC02.log
-rw-r–r-- 1 dmdba dinstall 256M May 11 21:51 dm8/data/CJC/CJC01.log
可以看到，CJC01.log 时间较新，为CURRENT REDO;
模拟故障：
非current redo 丢失
SQL> host mv dm8/data/CJC/CJC02.log dm8/data/CJC/CJC02.log.bak
SQL> shutdown abort;
启动
[dmdba@cjc-db-01 CJC]$ dmserver dm.ini
前台报错：
/dm8/data/CJC/CJC02.log not exist, can not startup
后台报错：
[dmdba@cjc-db-01 log]$ tail -10f dm_CJC_202405.log
2024-05-11 22:00:21.283 [FATAL] database P0000008747 T0000000000000008747 dm8/data/CJC/CJC02.log not exist,can not startup
启动数据库，找不到CJC02.og，导致启动失败。
用现有的REDO冒充丢失的REDO
[dmdba@cjc-db-01 CJC]$ cp CJC01.log CJC02.log
启动
[dmdba@cjc-db-01 CJC]$ dmserver dm.ini
前台报错
rfil grp init log file dm8/data/CJC/CJC02.log error, code = -717
后台报错
2024-05-11 22:02:32.168 [INFO] database P0000008964 T0000000000000008964 rfil[/dm8/data/CJC/CJC01.log] ver: 7007, sta: 0, arch_lsn = 0, arch_seq = 0, clsn = 44660, clsn_fil = 0, clsn_off = 17547264, l_next_seq = 5058, g_next_seq = 5058, free = 17567744, rpkg_crc_stand = 1
2024-05-11 22:02:32.168 [ERROR] database P0000008964 T0000000000000008964 arch file(/dm8/data/CJC/CJC02.log) fil id check fail
2024-05-11 22:02:32.168 [ERROR] database P0000008964 T0000000000000008964 rfil grp init log file /dm8/data/CJC/CJC02.log error, code = -717
2024-05-11 22:02:32.168 [ERROR] database P0000008964 T0000000000000008964 rlog4_init_low->rfil_grp_alloc failed, alloc_only = 0!
2024-05-11 22:02:32.168 [ERROR] database P0000008964 T0000000000000008964 hlog_upgrade failed, rlog4_sys_init return code[-126]
查看报错：fil id check fail，因为两个REDO fil id不能相同，所以报错。
arch file(/dm8/data/CJC/CJC02.log) fil id check fail
使用dmmdbf工具修改 fil id
dmmdbf工具是什么？
https://eco.dameng.com/document/dm/zh-cn/ops/troubleshooting-human
工具介绍
Dmmdf 工具：主要对 DM 相关的文件的属性进行修改。支持的修改的文件类型有：dbf、rlog、original bak、bakset meta、bakset bkp、bakset，根据文件的不同，可修改的属性也有所不同，最主要的是修改 db_magic。
查看帮助信息
[dmdba@cjc-db-01 CJC]$ dmmdf help
version: 03134284172-20240321-222308-20093
Format: ./dmmdf KEYWORD=value
Example: ./dmmdf TYPE=1 FILE=/opt/data/DAMENG/SYSTEM.DBF
Keyword Explanation
TYPE type
1: for dbf
bp_flag=0: Modify the normal instance
bp_flag=1: Modify the BP instance of DPC
2: for rlog
3: for original bak
4: for bakset meta
5: for bakset bkp
6: for bakset
7: for database degrades
scope=1: Only supports from 0x0007000A to 0x00070009, file is dm.ctl path
scope=2: Only supports from 0x0007000B to 0x0007000A, file is dm.ini path
scope=3: Only supports from 0x0007000C to 0x0007000B for single node database, file is dm.ini path
8: for rlog degrades
scope=1 Supports from 0x7006 to 0x7005
scope=2 Supports from 0x7007 to 0x7006
9: for specified database upgrade(Only supports from V8.1.1.88(V7.1.7.88) to V8.1.1.100(V7.1.7.100)
10: for updating db_magic of database, file is dm.ini path, db_magic is which update to
bp_flag=0: Modify the normal instance
bp_flag=1: Modify the BP instance of DPC, also need page_size to be set
FILE file path
PAGE_SIZE for TYPE=10 BP_FLAG=1, the page size of the datafile, default 8192
DCR_INI dmdcr.ini path
SCOPE scope for database degrades when type=7 or 8
BP_FLAG whether to modify the BP instance of DPC when type=1 or type=10, default not(0)
DB_MAGIC target db_magic when type=10
HELP show this help info
Example: ./dmmdf TYPE=1 FILE=/opt/data/DAMENG/SYSTEM.dbf
./dmmdf TYPE=2 FILE=/opt/data/DAMENG/DAMENG01.log
./dmmdf TYPE=3 FILE=/opt/data/DAMENG/bak/dmdb.bak
./dmmdf TYPE=4 FILE=/opt/data/DAMENG/bak/bset/nbak.meta
./dmmdf TYPE=5 FILE=/opt/data/DAMENG/bak/bset/nbak.bak
./dmmdf TYPE=6 FILE=/opt/data/DAMENG/bak/bset
./dmmdf TYPE=7 SCOPE=1 FILE=/opt/data/DAMENG/dm.ctl
./dmmdf TYPE=7 SCOPE=2 FILE=/opt/data/DAMENG/dm.ini
./dmmdf TYPE=7 SCOPE=3 FILE=/opt/data/DAMENG/dm.ini
./dmmdf TYPE=8 SCOPE=1 FILE=/opt/data/DAMENG/dm.ini
./dmmdf TYPE=8 SCOPE=2 FILE=/opt/data/DAMENG/dm.ini
./dmmdf TYPE=9 FILE=/opt/data/DAMENG/dm.ini
./dmmdf TYPE=10 FILE=/opt/data/DAMENG/dm.ini DB_MAGIC=123456
修改CJC01.log，将13 fil_id = 0改成13 fil_id = 1
[dmdba@cjc-db-01 CJC]$ dmmdf TYPE=2 FILE=/dm8/data/CJC/CJC01.log
dmmdf V8
1 sig = DMRLOG
2 ver = 7007
3 chksum = 969006225
4 sta = 0
5 n_magic = 7
6 db_magic = 1516351486
7 len = 268435456
8 free = 17567744
9 clsn = 44660
10 clsn_fil = 0
11 clsn_off = 17547264
12 pemnt_magic = 1510880832
13 fil_id = 0
15 next_seq = 5058
16 g_next_seq = 5058
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000c
20 min_exec_version = V8.1.1.1
21 min_dct_version = 4
22 p_db_magic = 0
23 n_apply_ep = 0
24 apply_info_lsn = 0
pkg_seq_arr: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
apply_lsn_arr: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
25 recv_p_db_magic = 0
26 recv_n_apply_ep = 0
recv_pkg_seq_arr: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
recv_apply_lsn_arr: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
27 l_term_id = 0
28 term_id = 0
29 c_seqno = 5057
30 c_lsn = 44661
31 rpkg_crc_stand = 1
You can only reset sta(4) or db_magic (6) or clsn (9) or clsn_fil(10) or clsn_off(11) or pemnt_magic(12) or fil_id(13) or next_seq(15) or g_next_seq(16) or p_db_magic(22) or n_apply_ep(23).
Please input the num which one you want to change, q to quit: 13
Input the new value: 1
再次启动：
[dmdba@cjc-db-01 CJC]$ dmserver dm.ini
启动成功
ndct_db_load_info finished, code:0.
nsvr_process_before_open begin.
nsvr_process_before_open success.
SYSTEM IS READY.
登录数据库，检查
[dmdba@cjc-db-01 CJC]$ disql SYSDBA/CJC123456:5238
Server[LOCALHOST:5238]:mode is normal, state is open
login used time : 15.570(ms)
disql V8
SQL> SELECT * FROM T1;
LINEID ID
1 1
2 2
3 3
4 4
5 5
used time: 1.535(ms). Execute id is 501.
SQL> INSERT INTO T1 VALUES(6);
affect rows 1
used time: 1.171(ms). Execute id is 502.
SQL> COMMIT;
executed successfully
used time: 8.523(ms). Execute id is 503.
current redo 丢失
方法一：失败
按照之前的方法，将另一个redo复制为丢失的redo,使用dmmdf工具只修改fil_id仍然无法启动数据库，
继续修改其他几个值，还是无法启动数据库
sta(4)
clsn (9) 44727
clsn_fil(10)
clsn_off(11) 17592320
fil_id(13) 0
next_seq(15) or 5068
g_next_seq(16) or 5068
方法二：失败
参考https://eco.dameng.com/解决方案，其他机器上重新创建一个相同名称、相同配置的实例，干净关库后考走redo文件到原库，手动修改db_magic等，无法解决问题。
报错如下：
2024-05-11 22:26:31.493 [INFO] database P0000010953 T0000000000000010953 main rfil[/dm8/data/CJC/CJC01.log]'s sta is active
2024-05-11 22:26:31.493 [ERROR] database P0000010953 T0000000000000010953 redo_rfil_grp_pwr_collect->rlog4_first_rpkg_seqno_get failed, code:-723
2024-05-11 22:26:31.494 [INFO] database P0000010953 T0000000000000010953 main rfil [/dm8/data/CJC/CJC01.log]'s grp collect 0 valid pwr record, discard 0 invalid pwr record
初步怀疑新版本对REDO增加了更严格的校验，具体恢复方法还要咨询原厂，有知道解决方法的欢迎留言。
参考链接：
https://eco.dameng.com/community/article/a702397bf5cb0aaf0d018e9cb1bee166
https://eco.dameng.com/community/article/1ffd251e3b2e82b08e0faf0eae9e345c
http://www.killdb.com/2021/08/27/%e8%be%be%e6%a2%a6%e6%95%b0%e6%8d%ae%e5%ba%93%e5%ad%a6%e4%b9%a0%e7%ac%94%e8%ae%b0%e4%b9%8b-current-redo%e8%af%af%e5%88%a0%e9%99%a4%e6%81%a2%e5%a4%8d/
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