前一篇文章测试了非current redo的情况，这里继续测试达梦数据库current redo如果被误删除如何启动数据库。
首先创建测试表，并删除current redo：
SQL> create table test_recovery as select * from dba_objects where rownum < 10;
executed successfully
used time: 25.033(ms). Execute id is 4.
SQL> select count(1) from test_recovery;
LINEID COUNT(1)
---------- --------------------
1 9
used time: 0.553(ms). Execute id is 5.
SQL> select owner,object_name,object_id from test_recovery;
LINEID OWNER OBJECT_NAME OBJECT_ID
---------- ------------ -------------- ---------
1 BENCHMARKSQL BENCHMARKSQL 150995945
2 CTISYS CTISYS 150994948
3 SYS SYS 150994944
4 SYSAUDITOR SYSAUDITOR 150994946
5 SYSDBA SYSDBA 150994945
6 SYSSSO SYSSSO 150994947
7 BENCHMARKSQL BMSQL_CONFIG 1421
8 BENCHMARKSQL BMSQL_CUSTOMER 1423
9 BENCHMARKSQL BMSQL_DISTRICT 1422
9 rows got
used time: 0.462(ms). Execute id is 6.
SQL> delete from test_recovery where OBJECT_ID in(1421,1422,1423);
affect rows 3
used time: 1.203(ms). Execute id is 7.
SQL> select CKPT_LSN,FILE_LSN,FLUSH_LSN,CUR_LSN,DB_MAGIC,FLUSH_PAGES,CKPT_FILE,CKPT_OFFSET,TOTAL_SPACE,FREE_SPACE from v$rlog;
LINEID CKPT_LSN FILE_LSN FLUSH_LSN CUR_LSN DB_MAGIC FLUSH_PAGES CKPT_FILE CKPT_OFFSET TOTAL_SPACE FREE_SPACE
---------- -------------------- -------------------- -------------------- -------------------- -------------------- ----------- ----------- -------------------- -------------------- --------------------
1 86572726 86573150 86573150 86573150 148545590 0 0 2528081920 9504272384 9504219648
used time: 0.741(ms). Execute id is 8.
SQL> select file_id,path,rlog_size from v$rlogfile;
LINEID FILE_ID PATH RLOG_SIZE
---------- ----------- ------------------------------------------- --------------------
1 0 /opt/dm/dmdbms/data/enmotech/enmotech01.log 3145728000
2 1 /opt/dm/dmdbms/data/enmotech/enmotech02.log 3145728000
3 2 /opt/dm/dmdbms/data/enmotech/enmotech03.log 3145728000
4 3 /opt/dm/dmdbms/data/enmotech/enmotech04.log 33554432
5 4 /opt/dm/dmdbms/data/enmotech/enmotech05.log 33554432
used time: 1.081(ms). Execute id is 9.
SQL> host rm -rf /opt/dm/dmdbms/data/enmotech/enmotech01.log
SQL> shutdown abort;
executed successfully
used time: 0.479(ms). Execute id is 0.
SQL>
此时尝试去启动数据库，肯定是会报错的；如下所示：
[dmdba@mogdb ~]$ DmServicedmdb start
Starting DmServicedmdb: [ FAILED ]
file dm.key not found, use default license!
version info: develop
Use normal os_malloc instead of HugeTLB
Use normal os_malloc instead of HugeTLB
DM Database Server x64 V8 1-1-126-20.09.04-126608-ENT startup...
Database mode = 0, oguid = 0
/opt/dm/dmdbms/data/enmotech/enmotech01.log not exist, can not startup
[dmdba@mogdb ~]$
这里我们利用其他2个日志来构造修改被删除的enmotech01.log。
[dmdba@mogdb ~]$ cp /opt/dm/dmdbms/data/enmotech/enmotech02.log /opt/dm/dmdbms/data/enmotech/enmotech01.log
[dmdba@mogdb ~]$
使用工具修复redo：
[root@mogdb bin]# ./dmmdf type=2 file=/opt/dm/dmdbms/data/enmotech/enmotech01.log
dmmdf V8
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -2123134874
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 1
15 next_seq = 0
16 g_next_seq = 0
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
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 g_next_seq(16) or p_db_magic(20) or n_apply_ep(21).
Please input the num which one you want to change, q to quit: 13
Input the new value: 0
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -2123134873
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 0
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
Do you want to quit and save the change to file (y/n): y
Save to file success!
再次启动发现仍然报错：
[dmdba@mogdb ~]$ DmServicedmdb start
Starting DmServicedmdb: [ FAILED ]
file dm.key not found, use default license!
version info: develop
Use normal os_malloc instead of HugeTLB
Use normal os_malloc instead of HugeTLB
DM Database Server x64 V8 1-1-126-20.09.04-126608-ENT startup...
Database mode = 0, oguid = 0
License will expire on 2021-09-10
EP[0]'s cur_lsn[0]
[dmdba@mogdb ~]$
检查日志发现相关信息是不对的：
2021-08-27 01:38:28.254 [WARNING] database P0000039507 T0000000000000039507 License will expire on 2021-09-10
2021-08-27 01:38:28.256 [INFO] database P0000039507 T0000000000000039507 Initialize temp tablespace, file path: /opt/dm/dmdbms/data/enmotech/TEMP.DBF, code: 0
2021-08-27 01:38:28.262 [INFO] database P0000039507 T0000000000000039507 rfil[/opt/dm/dmdbms/data/enmotech/enmotech01.log] ver: 7006, sta: 0, arch_lsn = 0, arch_seq = 0, clsn = 0, clsn_fil = 0, clsn_off = 0, l_next_seq = 0, g_next_seq = 0, free = 2528041472
2021-08-27 01:38:28.263 [INFO] database P0000039507 T0000000000000039507 rlog4_apply_info_set, p_db_magic:[0x0](old value:0x0), n_apply_ep: 0(old n_ep=0), apply_info_lsn: 0(old 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]
2021-08-27 01:38:28.263 [INFO] database P0000039507 T0000000000000039507 hlog_sys_destroy, n_logs[1], adjust_sta[0]
2021-08-27 01:38:28.264 [INFO] database P0000039507 T0000000000000039507 rfil[/opt/dm/dmdbms/data/enmotech/enmotech01.log] ver: 7006, sta: 0, arch_lsn = 0, arch_seq = 0, clsn = 0, clsn_fil = 0, clsn_off = 0, l_next_seq = 0, g_next_seq = 0, free = 2528041472
2021-08-27 01:38:28.265 [INFO] database P0000039507 T0000000000000039507 rlog4_apply_info_set, p_db_magic:[0x0](old value:0x0), n_apply_ep: 0(old n_ep=0), apply_info_lsn: 0(old 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]
2021-08-27 01:38:28.270 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:0, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.273 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:1, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.277 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:2, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.280 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:3, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.284 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:4, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.288 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:5, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.291 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:6, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.295 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:7, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.298 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:8, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.306 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:9, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.311 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:10, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.314 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:11, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.317 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:12, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.321 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:13, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.325 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:14, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.330 [INFO] database P0000039507 T0000000000000039507 plog_redo_init, rlog is null, dsc_seqno:15, set plog_redo->redo_lsn from 0 to 0
2021-08-27 01:38:28.381 [INFO] database P0000039507 T0000000000000039507 main rfil[/opt/dm/dmdbms/data/enmotech/enmotech01.log]'s sta is active
2021-08-27 01:38:28.381 [ERROR] database P0000039507 T0000000000000039507 Read rfil['/opt/dm/dmdbms/data/enmotech/enmotech01.log'] from offset[0] failed, code[-723]
2021-08-27 01:38:28.381 [INFO] database P0000039507 T0000000000000039507 rfil[/opt/dm/dmdbms/data/enmotech/enmotech01.log], first local_rpkg_seqno = 0, global_rpkg_seqno = 0, first_startup = 0
2021-08-27 01:38:28.381 [INFO] database P0000039507 T0000000000000039507 EP[0]'s cur_lsn[0]
2021-08-27 01:38:28.381 [FATAL] database P0000039507 T0000000000000039507 redo_pwr_collect error, code = -723
2021-08-27 01:38:28.382 [INFO] database P0000039507 T0000000000000039507 hlog_sys_destroy, n_logs[1], adjust_sta[0]
进一步检查之前的日志，寻找lsn等信息：
2021-08-27 01:28:46.940 [INFO] database P0000032604 T0000000000000032607 shutdown redo log subsystem...
2021-08-27 01:28:46.940 [INFO] database P0000032604 T0000000000000032607 rfil_close_low set main rfil[/opt/dm/dmdbms/data/enmotech/enmotech01.log]'s sta to inactive, l_next_seq = 739034, g_next_seq = 739034, clsn = 86572726, handle = 7, free=2528081920, len=3145728000
2021-08-27 01:28:46.942 [INFO] database P0000032604 T0000000000000032607 os_sema2_free, sema_id:32768, sema_value:1!
2021-08-27 01:28:46.953 [INFO] database P0000032604 T0000000000000032607 shutdown MAL subsystem...
2021-08-27 01:28:47.004 [FATAL] database P0000032604 T0000000000000032604 sigterm_handler receive signal 2
再次进行修改：
[root@mogdb bin]# ./dmmdf type=2 file=/opt/dm/dmdbms/data/enmotech/enmotech01.log
dmmdf V8
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -2123134873
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 0
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
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 g_next_seq(16) or p_db_magic(20) or n_apply_ep(21).
Please input the num which one you want to change, q to quit: 16
Input the new value: 739034
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1976216985
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
Do you want to quit and save the change to file (y/n): y
Save to file success!
[root@mogdb bin]#
[root@mogdb bin]#
[root@mogdb bin]# ./dmmdf type=2 file=/opt/dm/dmdbms/data/enmotech/enmotech01.log
dmmdf V8
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1976216985
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
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 g_next_seq(16) or p_db_magic(20) or n_apply_ep(21).
Please input the num which one you want to change, q to quit: 9
Input the new value: 86572726
ERROR, rlog is active, dmserver should shutdown normal.
[root@mogdb bin]#
看上去修改不对，提示这个redo log状态是inactive。那么首先修改成active，试试看；
[root@mogdb bin]# ./dmmdf type=2 file=/opt/dm/dmdbms/data/enmotech/enmotech01.log
dmmdf V8
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1976216985
4 sta = 0
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
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 g_next_seq(16) or p_db_magic(20) or n_apply_ep(21).
Please input the num which one you want to change, q to quit: 4
Input the new value: 1
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1976216986
4 sta = 1
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
Do you want to quit and save the change to file (y/n): y
Save to file success!
[root@mogdb bin]# ./dmmdf type=2 file=/opt/dm/dmdbms/data/enmotech/enmotech01.log
dmmdf V8
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1976216986
4 sta = 1
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 0
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
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 g_next_seq(16) or p_db_magic(20) or n_apply_ep(21).
Please input the num which one you want to change, q to quit: 9
Input the new value: 86572726
**********************************************************
1 sig = DMRLOG
2 ver = 7006
3 chksum = -1893880624
4 sta = 1
5 n_magic = 7
6 db_magic = 148545590
7 len = 3145728000
8 free = 2528041472
9 clsn = 86572726
10 clsn_fil = 0
11 clsn_off = 0
12 pemnt_magic = 272050232
13 fil_id = 0
15 next_seq = 0
16 g_next_seq = 739034
17 arch_lsn = 0
18 arch_seq = 0
19 dbversion = 0x7000b
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)
**********************************************************
Do you want to quit and save the change to file (y/n): y
Save to file success!
[root@mogdb bin]#
Ok！自此修改完毕，接下来我们尝试启动达梦数据库看看效果。
[dmdba@mogdb ~]$ DmServicedmdb start
Starting DmServicedmdb: [ OK ]
[dmdba@mogdb ~]$
[dmdba@mogdb ~]$
最后我们验证一下数据库：
[dmdba@mogdb enmotech]$ disql sysdba/roger007
Server[LOCALHOST:5236]:mode is normal, state is open
login used time : 3.007(ms)
disql V8
SQL> select file_id,path,rlog_size from v$rlogfile;
LINEID FILE_ID PATH RLOG_SIZE
---------- ----------- ------------------------------------------- --------------------
1 0 /opt/dm/dmdbms/data/enmotech/enmotech01.log 3145728000
2 1 /opt/dm/dmdbms/data/enmotech/enmotech02.log 3145728000
3 2 /opt/dm/dmdbms/data/enmotech/enmotech03.log 3145728000
4 3 /opt/dm/dmdbms/data/enmotech/enmotech04.log 33554432
5 4 /opt/dm/dmdbms/data/enmotech/enmotech05.log 33554432
used time: 3.137(ms). Execute id is 4.
SQL> select owner,object_name,object_id from test_recovery;
LINEID OWNER OBJECT_NAME OBJECT_ID
---------- ------------ -------------- ---------
1 BENCHMARKSQL BENCHMARKSQL 150995945
2 CTISYS CTISYS 150994948
3 SYS SYS 150994944
4 SYSAUDITOR SYSAUDITOR 150994946
5 SYSDBA SYSDBA 150994945
6 SYSSSO SYSSSO 150994947
7 BENCHMARKSQL BMSQL_CONFIG 1421
8 BENCHMARKSQL BMSQL_CUSTOMER 1423
9 BENCHMARKSQL BMSQL_DISTRICT 1422
9 rows got
used time: 5.998(ms). Execute id is 5.
SQL>
可以发现数据库正常，数据也是正常的。不过通过综合分析，发现达梦数据库似乎在事务一致性方面校验并不是十分的严格。
后面我进行了类似多次测试，如下：
SQL> select owner,object_name,object_id from test_recovery;
LINEID OWNER OBJECT_NAME OBJECT_ID
---------- ------------ ------------ ---------
1 BENCHMARKSQL BENCHMARKSQL 150995945
2 CTISYS CTISYS 150994948
3 SYS SYS 150994944
4 SYSAUDITOR SYSAUDITOR 150994946
5 SYSDBA SYSDBA 150994945
6 SYSSSO SYSSSO 150994947
6 rows got
used time: 7.054(ms). Execute id is 5.
SQL>
SQL>
SQL>
SQL> delete from test_recovery where OBJECT_ID=150995945
2 ;
affect rows 1
used time: 7.161(ms). Execute id is 6.
SQL> select checkpoint(100);
LINEID CHECKPOINT(100)
---------- ---------------
1 0
used time: 3.501(ms). Execute id is 7.
SQL> /
LINEID CHECKPOINT(100)
---------- ---------------
1 0
used time: 3.287(ms). Execute id is 8.
SQL> /
LINEID CHECKPOINT(100)
---------- ---------------
1 0
used time: 103.138(ms). Execute id is 9.
SQL> select CKPT_LSN,FILE_LSN,FLUSH_LSN,CUR_LSN,DB_MAGIC,FLUSH_PAGES,CKPT_FILE,CKPT_OFFSET,TOTAL_SPACE,FREE_SPACE from v$rlog;
LINEID CKPT_LSN FILE_LSN FLUSH_LSN CUR_LSN DB_MAGIC FLUSH_PAGES CKPT_FILE CKPT_OFFSET TOTAL_SPACE FREE_SPACE
---------- -------------------- -------------------- -------------------- -------------------- -------------------- ----------- ----------- -------------------- -------------------- --------------------
1 86573321 86573321 86573321 86573321 148545590 0 0 35328 9504272384 9504272384
used time: 1.557(ms). Execute id is 10.
SQL> select file_id,path,rlog_size from v$rlogfile;
LINEID FILE_ID PATH RLOG_SIZE
---------- ----------- ------------------------------------------- --------------------
1 0 /opt/dm/dmdbms/data/enmotech/enmotech01.log 3145728000
2 1 /opt/dm/dmdbms/data/enmotech/enmotech02.log 3145728000
3 2 /opt/dm/dmdbms/data/enmotech/enmotech03.log 3145728000
4 3 /opt/dm/dmdbms/data/enmotech/enmotech04.log 33554432
5 4 /opt/dm/dmdbms/data/enmotech/enmotech05.log 33554432
used time: 1.226(ms). Execute id is 11.
SQL> host rm -rf /opt/dm/dmdbms/data/enmotech/enmotech01.log
SQL> shutdown abort;
executed successfully
used time: 3.585(ms). Execute id is 0.
SQL>
修改redo的步骤类似，这里省略。
[dmdba@mogdb ~]$ DmServicedmdb start
Starting DmServicedmdb: [ OK ]
[dmdba@mogdb ~]$
SQL> select instance_name,status$ from v$instance;
LINEID INSTANCE_NAME STATUS$
---------- ------------- -------
1 DMDB OPEN
used time: 3.383(ms). Execute id is 4.
SQL> select owner,object_name,object_id from test_recovery;
LINEID OWNER OBJECT_NAME OBJECT_ID
---------- ------------ ------------ ---------
1 BENCHMARKSQL BENCHMARKSQL 150995945
2 CTISYS CTISYS 150994948
3 SYS SYS 150994944
4 SYSAUDITOR SYSAUDITOR 150994946
5 SYSDBA SYSDBA 150994945
6 SYSSSO SYSSSO 150994947
6 rows got
used time: 4.907(ms). Execute id is 5.
SQL>
数据仍然正常，此时日志中有事务回滚方面的信息：
2021-08-27 02:04:22.577 [INFO] database P0000041271 T0000000000000041271 total 1 active crash trx, pseg_crash_trx_rollbacksys_only(0) begin ...
2021-08-27 02:04:22.577 [INFO] database P0000041271 T0000000000000041271 rollback trx[860480], locks[2], first_fpa(1, 0, 40159), last_fpa(1, 0, 40159), n_pages(1)
2021-08-27 02:04:22.577 [INFO] database P0000041271 T0000000000000041271 trx: 860480 rollbacking...
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 total 1 page rollbacked, rollback percent: 100%
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 total 1 trx rollbacked, rollback percent: 100%
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 table: TEST_RECOVERY, schema id: 150994945, table id: 1454 rollback in trx
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 trx: 860480 rollback 1 upages, 2 urecs end
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 pseg_crash_trx_rollback end, total 1 active crash trx, include 0 empty_trxs, 0 empty_pages which only need to delete mgr recs.
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 pseg_crash_trx_rollback end
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 pseg_crash_trx_rollback all active trx used 1(ms), mgr_state:1!
2021-08-27 02:04:22.578 [INFO] database P0000041271 T0000000000000041271 pseg_sys_recv used 7ms!
2021-08-27 02:04:22.581 [INFO] database P0000041271 T0000000000000041271 pseg recv finished
2021-08-27 02:04:22.582 [INFO] database P0000041271 T0000000000000041271 nsvr_startup end.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 aud sys init success.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 aud rt sys init success.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 systables desc init success.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 ndct_db_load_info success.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 nsvr_process_before_open begin.
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 Update DM8_DCT_VERSION from 20 to 20, rebuild dynamic tables begin...
2021-08-27 02:04:22.683 [INFO] database P0000041271 T0000000000000041271 Update DM8_DCT_VERSION from 20 to 20, rebuild dynamic tables end.
2021-08-27 02:04:22.739 [INFO] database P0000041271 T0000000000000041271 nsvr_process_before_open success.
2021-08-27 02:04:22.739 [INFO] database P0000041271 T0000000000000041295 total 0 active crash trx, pseg_crash_trx_rollbacksys_only(0) begin ...
2021-08-27 02:04:22.739 [INFO] database P0000041271 T0000000000000041295 pseg_crash_trx_rollback end, total 0 active crash trx, include 0 empty_trxs, 0 empty_pages which only need to delete mgr recs.
2021-08-27 02:04:22.739 [INFO] database P0000041271 T0000000000000041295 pseg_crash_trx_rollback end
2021-08-27 02:04:22.743 [INFO] database P0000041271 T0000000000000041271 backup control file /opt/dm/dmdbms/data/enmotech/dm.ctl to file /opt/dm/dmdbms/data/enmotech/dm_20210827020422_743043.ctl
2021-08-27 02:04:22.744 [INFO] database P0000041271 T0000000000000041271 backup control file /opt/dm/dmdbms/data/enmotech/dm.ctl to file /opt/dm/dmdbms/data/enmotech/ctl_bak/dm_20210827020422_743940.ctl succeed
2021-08-27 02:04:22.744 [INFO] database P0000041271 T0000000000000041271 local instance name is DMDB, mode is NORMAL, status is OPEN.
这里让我有点看不懂了。难道事务恢复不需要Redo？我只需要Redo的几个关键信息就可以欺骗达梦数据库？
「喜欢这篇文章，您的关注和赞赏是给作者最好的鼓励」
关注作者
【版权声明】本文为墨天轮用户原创内容，转载时必须标注文章的来源（墨天轮），文章链接，文章作者等基本信息，否则作者和墨天轮有权追究责任。如果您发现墨天轮中有涉嫌抄袭或者侵权的内容，欢迎发送邮件至：contact@modb.pro进行举报，并提供相关证据，一经查实，墨天轮将立刻删除相关内容。
