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最新推荐文章于 2023-12-02 22:53:12 发布

转载最新推荐文章于 2023-12-02 22:53:12 发布 · 820 阅读

本文详细解析了Oracle数据库中的redo日志与数据文件记录，包括redo log的切换过程、SCN的更新机制以及数据文件的checkpoint信息。通过具体实例展示了不同redo日志文件的状态及其包含的时间戳、SCN等关键信息。

***************************************************************************
LOG FILE RECORDS redo log file信息
***************************************************************************
(size = 72, compat size = 72, section max = 16, section in-use = 3,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 10, numrecs = 16)
LOG FILE #1:
(name #3) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\REDO01.LOG
Thread 1 redo log links: forward: 2 backward: 0
siz: 0x19000 seq: 0x00000008 hws: 0xa bsz: 512 nab: 0x4ac1 flg: 0x1 dup: 1
Archive links: fwrd: 0 back: 0 Prev scn: 0x0000.000f340f
Low scn: 0x0000.000feccc 05/12/2011 07:55:39
Next scn: 0x0000.00107564 05/13/2011 07:48:16

-- 在一个事务提交后，会在redo log中存在一条redo记录，同时，系统为其
提供一个最新的SCN，记录在该条记录中。如果该条记录是在redo log被清空
（日志满做切换时或发生checkpoint时，所有变化日志已经被写入数据文件中），
则其SCN被记录为redo log的low SCN。以后在日志再次被清空前写入的redo记
录中SCN则成为Next SCN。

LOG FILE #2:
(name #2) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\REDO02.LOG
Thread 1 redo log links: forward: 3 backward: 1
siz: 0x19000 seq: 0x00000009 hws: 0x6 bsz: 512 nab: 0x6636 flg: 0x1 dup: 1
Archive links: fwrd: 0 back: 0 Prev scn: 0x0000.000feccc
Low scn: 0x0000.00107564 05/13/2011 07:48:16
Next scn: 0x0000.001115f2 05/16/2011 07:37:21
LOG FILE #3:
(name #1) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\REDO03.LOG
Thread 1 redo log links: forward: 0 backward: 2
siz: 0x19000 seq: 0x0000000a hws: 0x5 bsz: 512 nab: 0xffffffff flg: 0x8 dup: 1
Archive links: fwrd: 0 back: 0 Prev scn: 0x0000.00107564
Low scn: 0x0000.001115f2 05/16/2011 07:37:21
Next scn: 0xffff.ffffffff 01/01/1988 00:00:00

-- 可以注意到，在current redo中，next scn是无穷大(redo 3是current).

***************************************************************************
DATA FILE RECORDS
***************************************************************************
(size = 428, compat size = 428, section max = 100, section in-use = 4,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 11, numrecs = 100)
DATA FILE #1:
(name #7) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\SYSTEM01.DBF
creation size=0 block size=8192 status=0xe head=7 tail=7 dup=1
tablespace 0, index=1 krfil=1 prev_file=0
unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
Checkpoint cnt:128 scn: 0x0000.00111793 05/17/2011 07:38:56
Stop scn: 0xffff.ffffffff 05/16/2011 07:39:49
Creation Checkpointed at scn: 0x0000.00000009 08/30/2005 13:50:22
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
......
00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x0000.00000000 prev_range: 0
Online Checkpointed at scn: 0x0000.00000000
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
......
00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000.00000000
-- 热备份end 记录scn

aux_file is NOT DEFINED
DATA FILE #2:
(name #6) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\UNDOTBS01.DBF
creation size=0 block size=8192 status=0xe head=6 tail=6 dup=1
tablespace 1, index=2 krfil=2 prev_file=0
unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
Checkpoint cnt:91 scn: 0x0000.00111793 05/17/2011 07:38:56
Stop scn: 0xffff.ffffffff 05/16/2011 07:39:49
Creation Checkpointed at scn: 0x0000.00081f74 08/30/2005 17:25:44
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
......
00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x0000.00000000 prev_range: 0
Online Checkpointed at scn: 0x0000.00000000
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
......
00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000.00000000
aux_file is NOT DEFINED
DATA FILE #3:
(name #5) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\SYSAUX01.DBF
creation size=0 block size=8192 status=0xe head=5 tail=5 dup=1
tablespace 2, index=3 krfil=3 prev_file=0
unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
Checkpoint cnt:128 scn: 0x0000.00111793 05/17/2011 07:38:56
Stop scn: 0xffff.ffffffff 05/16/2011 07:39:49
Creation Checkpointed at scn: 0x0000.000017d4 08/30/2005 13:50:49
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
.....
00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x0000.00000000 prev_range: 0
Online Checkpointed at scn: 0x0000.00000000
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
.....
00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000.00000000
aux_file is NOT DEFINED
DATA FILE #4:
(name #4) D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST01\USERS01.DBF
creation size=0 block size=8192 status=0xe head=4 tail=4 dup=1
tablespace 4, index=4 krfil=4 prev_file=0
unrecoverable scn: 0x0000.00000000 01/01/1988 00:00:00
Checkpoint cnt:127 scn: 0x0000.00111793 05/17/2011 07:38:56
Stop scn: 0xffff.ffffffff 05/16/2011 07:39:49
Creation Checkpointed at scn: 0x0000.00002629 08/30/2005 13:51:05
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
......
00000000 00000000 00000000 00000000 00000000 00000000
Offline scn: 0x0000.00000000 prev_range: 0
Online Checkpointed at scn: 0x0000.00000000
thread:0 rba:(0x0.0.0)
enabled threads: 00000000 00000000 00000000 00000000 00000000 00000000
.......
00000000 00000000 00000000 00000000 00000000 00000000
Hot Backup end marker scn: 0x0000.00000000
aux_file is NOT DEFINED

***************************************************************************
TEMP FILE RECORDS
***************************************************************************
(size = 56, compat size = 56, section max = 100, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 89, numrecs = 100)

***************************************************************************
TABLESPACE RECORDS
***************************************************************************
(size = 68, compat size = 68, section max = 100, section in-use = 5,
last-recid= 1, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 88, numrecs = 100)
TABLESPACE #0 SYSTEM: recno=1
First datafile link=1 Tablespace Flag=0
Tablespace PITR mode start scn: 0x0000.00000000 01/01/1988 00:00:00
Tablespace PITR last completion scn: 0x0000.00000000 01/01/1988 00:00:00
TABLESPACE #1 UNDOTBS1: recno=2
First datafile link=2 Tablespace Flag=0
Tablespace PITR mode start scn: 0x0000.00000000 01/01/1988 00:00:00
Tablespace PITR last completion scn: 0x0000.00000000 01/01/1988 00:00:00
TABLESPACE #2 SYSAUX: recno=3
First datafile link=3 Tablespace Flag=0
Tablespace PITR mode start scn: 0x0000.00000000 01/01/1988 00:00:00
Tablespace PITR last completion scn: 0x0000.00000000 01/01/1988 00:00:00
TABLESPACE #4 USERS: recno=4
First datafile link=4 Tablespace Flag=0
Tablespace PITR mode start scn: 0x0000.00000000 01/01/1988 00:00:00
Tablespace PITR last completion scn: 0x0000.00000000 01/01/1988 00:00:00
TABLESPACE #3 TEMP: recno=5
First datafile link=0 Tablespace Flag=1
Tablespace PITR mode start scn: 0x0000.00000000 01/01/1988 00:00:00
Tablespace PITR last completion scn: 0x0000.00000000 01/01/1988 00:00:00

***************************************************************************
RMAN CONFIGURATION RECORDS    RMAN配置记录
***************************************************************************
(size = 1108, compat size = 1108, section max = 50, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 90, numrecs = 50)

***************************************************************************
FLASHBACK LOGFILE RECORDS      闪回日志记录
***************************************************************************
(size = 84, compat size = 84, section max = 2048, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 149, numrecs = 2048)

***************************************************************************
THREAD INSTANCE MAPPING RECORDS
***************************************************************************
(size = 80, compat size = 80, section max = 8, section in-use = 8,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 166, numrecs = 8)
test01 recno=1
UNNAMED_INSTANCE_2 recno=2
UNNAMED_INSTANCE_3 recno=3
UNNAMED_INSTANCE_4 recno=4
UNNAMED_INSTANCE_5 recno=5
UNNAMED_INSTANCE_6 recno=6
UNNAMED_INSTANCE_7 recno=7
UNNAMED_INSTANCE_8 recno=8

***************************************************************************
MTTR RECORDS
***************************************************************************
(size = 100, compat size = 100, section max = 8, section in-use = 1,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 167, numrecs = 8)
MTTR record for thread 1
MTTR statistics status: 1
Init time: Avg: 61418885 us, Times measured: 4
File open time: Avg: 157673 us, Times measured: 13
Log block read time: Avg: 20 us, Times measured: 65536
Data block read/claim time: Avg: 170 us, Times measured: 1000
Data block write time: Avg: 390 us
1000 change vector apply time: Avg: 0 us, Times measured: 1
Ratio Information:
# of log blocks measured: 156064
# of data blocks measured: 8289
# of change vectors measured: 529360

***************************************************************************
STANDBY DATABASE MAP RECORDS
***************************************************************************
(size = 400, compat size = 400, section max = 10, section in-use = 10,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 170, numrecs = 10)

***************************************************************************
RESTORE POINT RECORDS
***************************************************************************
(size = 212, compat size = 212, section max = 2048, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 171, numrecs = 2048)

***************************************************************************
LOG FILE HISTORY RECORDS
***************************************************************************
(size = 56, compat size = 56, section max = 292, section in-use = 6,
last-recid= 6, old-recno = 1, last-recno = 6)
(extent = 1, blkno = 94, numrecs = 292)
Earliest record:
RECID #1 Recno 1 Record timestamp 04/28/11 11:32:27 Thread=1 Seq#=4 Link-Recid=0 kccic-Recid=1
Low scn: 0x0000.000e43da 04/28/11 11:27:15 Next scn: 0x0000.000e4549
Latest record:
RECID #6 Recno 6 Record timestamp 05/16/11 07:37:22 Thread=1 Seq#=9 Link-Recid=5 kccic-Recid=1
Low scn: 0x0000.00107564 05/13/11 07:48:16 Next scn: 0x0000.001115f2
RECID #5 Recno 5 Record timestamp 05/13/11 07:48:16 Thread=1 Seq#=8 Link-Recid=4 kccic-Recid=1
Low scn: 0x0000.000feccc 05/12/11 07:55:39 Next scn: 0x0000.00107564
RECID #4 Recno 4 Record timestamp 05/12/11 07:55:39 Thread=1 Seq#=7 Link-Recid=3 kccic-Recid=1
Low scn: 0x0000.000f340f 05/03/11 07:32:37 Next scn: 0x0000.000feccc
RECID #3 Recno 3 Record timestamp 05/03/11 07:32:37 Thread=1 Seq#=6 Link-Recid=2 kccic-Recid=1
Low scn: 0x0000.000ee550 05/01/11 09:15:30 Next scn: 0x0000.000f340f
RECID #2 Recno 2 Record timestamp 05/01/11 09:15:30 Thread=1 Seq#=5 Link-Recid=1 kccic-Recid=1
Low scn: 0x0000.000e4549 04/28/11 11:32:27 Next scn: 0x0000.000ee550
RECID #1 Recno 1 Record timestamp 04/28/11 11:32:27 Thread=1 Seq#=4 Link-Recid=0 kccic-Recid=1
Low scn: 0x0000.000e43da 04/28/11 11:27:15 Next scn: 0x0000.000e4549

***************************************************************************
OFFLINE RANGE RECORDS    offline范围记录
***************************************************************************
(size = 200, compat size = 200, section max = 163, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 95, numrecs = 163)