OGG 11g Checkpoint 详解

OGG Checkpoint 详解

 

定位中断的位置，下次启动从中断的位置开始恢复。

 

 

1.target  端配置；

2.一条记录对应一个replicat

 

一. Extract Checkpoints

 (1) Extract read checkpoints

         （1） Startup checkpoint   --ogg启动的时候创建

          当Extract 进程启动的时候，会创建startup checkpoint，用来记录此时record的相关信息。该     checkpoint    是第一个checkpoint。
          startup checkpoint的统计信息包含如下内容：
        （1） Thread #: 创建checkpoint 的thread编号。
        （2） Sequence #:创建checkpoint 时对应的sequence 号码。  --list archive log;
        （3） RBA: 创建checkpoint 时，redo log 里面record 的relative byte address。
        （4）Timestamp:  创建checkpoint 时record对应的timestamp。
        （5）SCN: 创建checkpoint 时 record 对应的system change number 。
        （6）Redo File: 创建checkpoint 时record对应的事务日志路径。

 

 2 ) Recovery checkpoint

      recover checkpoint 记录的是data source（online redo log 或者归档中）中Extract 最久没处理的record的位置。 该checkpoint 的统计信息和startup checkpoint一样。

 

3) Current checkpoint

current checkpoint 是data source中Extract 最后一次读取的record的位置。

 

 

GGSCI (ogg02) 4>  info ext1

EXTRACT    EXT1      Last Started 2014-12-27 17:42   Status RUNNING
Checkpoint Lag          00:00:00 (updated 00:00:04 ago)
Process ID                31621
Log Read Checkpoint  Oracle Redo Logs
                     2014-12-27 18:06:05  Seqno 15, RBA 18128896
                     SCN 0.1142344 (1142344)

 

Seqno  和 RBA  会变，说明ogg是在工作的。

 

GGSCI (ogg02) 5>  info ext1,showch

EXTRACT    EXT1      Last Started 2014-12-27 17:42   Status RUNNING
Checkpoint Lag       00:00:00 (updated 00:00:00 ago)
Process ID           31621
Log Read Checkpoint  Oracle Redo Logs
                     2014-12-27 18:11:06  Seqno 15, RBA 18188800
                     SCN 0.1142472 (1142472)


Current Checkpoint Detail:

Read Checkpoint #1

  Oracle Redo Log

  Startup Checkpoint (starting position in the data source):
    Thread #: 1
    Sequence #: 11
    RBA: 7646224
    Timestamp: 2014-12-27 16:20:48.000000
    SCN: 0.1136079 (1136079)
    Redo File: /oradata/ogg02/redo02.log

  Recovery Checkpoint (position of oldest unprocessed transaction in the data source):
    Thread #: 1
    Sequence #: 15
    RBA: 18187792
    Timestamp: 2014-12-27 18:09:41.000000
    SCN: 0.1142443 (1142443)
    Redo File: /oradata/ogg02/redo03.log

  Current Checkpoint (position of last record read in the data source):
    Thread #: 1
    Sequence #: 15
    RBA: 18188800
    Timestamp: 2014-12-27 18:11:06.000000
    SCN: 0.1142472 (1142472)
    Redo File: /oradata/ogg02/redo03.log

Write Checkpoint #1

  GGS Log Trail

  Current Checkpoint (current write position):
    Sequence #: 4
    RBA: 1755
    Timestamp: 2014-12-27 18:11:43.251745
    Extract Trail: /u01/zt/dirdat/lt
    Trail Type: RMTTRAIL

Header:
  Version = 2
  Record Source = A
  Type = 10
  # Input Checkpoints = 1
  # Output Checkpoints = 1

File Information:
  Block Size = 2048
  Max Blocks = 100
  Record Length = 2048
  Current Offset = 0

Configuration:
  Data Source = 3
  Transaction Integrity = 1
  Task Type = 0

Status:
  Start Time = 2014-12-27 17:42:32
  Last Update Time = 2014-12-27 18:11:43
  Stop Status = A
  Last Result = 400

 

二.Extract write checkpoints

 

该checkpoint包含如下信息：
（1）Sequence #: checkpoint 正在写的trail 文件的序列号。
（2）RBA: 创建checkpoint 时trail文件里record 的relative byte address。
（3）Timestamp: 创建checkpoint 时record对应的timestamp。
（4）Extract trail: trail 文件的路径。
（5）Trail Type: 标识trail 文件类型。有2个值：
EXTTRAIL：表示该trail 是本地的trail，文件由OGG进程直接写如本地disk。
RMTTRAIL：表示是远程的trail，该文件不会写入本地的磁盘，而是传到远端的的OGG上，在有远端OGG的collector 进程写disk。 
比如pump 进程，里面就会写RMTTRAIL。

 

-----------------------------------------------------------------------------------------

target 端

 

GGSCI (ogg04) 1>  info rep1

REPLICAT   REP1      Last Started 2014-12-27 14:07   Status RUNNING
Checkpoint Lag         00:00:00 (updated 00:00:01 ago)
Process ID               26088
Log Read Checkpoint  File /u01/zt/dirdat/lt000004
                     2014-12-27 16:49:03.408880  RBA 1755

 

 

GGSCI (ogg04) 2>  info rep1,showch

REPLICAT   REP1      Last Started 2014-12-27 14:07   Status RUNNING
Checkpoint Lag         00:00:00 (updated 00:00:07 ago)
Process ID               26088
Log Read Checkpoint  File /u01/zt/dirdat/lt000004
                     2014-12-27 16:49:03.408880  RBA 1755


Current Checkpoint Detail:

Read Checkpoint #1

  GGS Log Trail

  Startup Checkpoint (starting position in the data source):
    Sequence #: 3
    RBA: 20259
    Timestamp: 2014-12-27 14:06:57.000000
    Extract Trail: /u01/zt/dirdat/lt

  Current Checkpoint (position of last record read in the data source):  --最后一次读取文件的位置
    Sequence #: 4
    RBA: 1755
    Timestamp: 2014-12-27 16:49:03.408880
    Extract Trail: /u01/zt/dirdat/lt

Header:
  Version = 2
  Record Source = A
  Type = 1
  # Input Checkpoints = 1
  # Output Checkpoints = 0

File Information:
  Block Size = 2048
  Max Blocks = 100
  Record Length = 2048
  Current Offset = 0

Configuration:
  Data Source = 0
  Transaction Integrity = -1
  Task Type = 0

Database Checkpoint:
  Checkpoint table = ggs.checkpoint
  Key = 982417365 (0x3a8e7fd5)
  Create Time = 2014-12-27 10:46:19

Status:
  Start Time = 2014-12-27 14:07:31
  Last Update Time = 2014-12-27 17:03:30
  Stop Status = A
  Last Result = 400

 

 GGSCI (ogg04) 3> info rep1    --看rba是否有变化

 

 

 

 

转：http://blog.csdn.net/zhengwei125/article/details/46503403