OGG 11g Checkpoint 详解
2024-07-21 02:52:52
供稿：网友
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 checkpointcurrent checkpoint 是data source中Extract 最后一次读取的record的位置。GGSCI (ogg02) 4> info ext1EXTRACT EXT1 Last Started 2014-12-27 17:42 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:04 ago)PRocess ID 31621Log 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,showchEXTRACT EXT1 Last Started 2014-12-27 17:42 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:00 ago)Process ID 31621Log 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.logWrite 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: RMTTRAILHeader: Version = 2 Record Source = A Type = 10 # Input Checkpoints = 1 # Output Checkpoints = 1File Information: Block Size = 2048 Max Blocks = 100 Record Length = 2048 Current Offset = 0Configuration: Data Source = 3 Transaction Integrity = 1 Task Type = 0Status: 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 rep1REPLICAT REP1 Last Started 2014-12-27 14:07 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:01 ago)Process ID 26088Log Read Checkpoint File /u01/zt/dirdat/lt000004 2014-12-27 16:49:03.408880 RBA 1755GGSCI (ogg04) 2> info rep1,showchREPLICAT REP1 Last Started 2014-12-27 14:07 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:07 ago)Process ID 26088Log Read Checkpoint File /u01/zt/dirdat/lt000004 2014-12-27 16:49:03.408880 RBA 1755Current 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/ltHeader: Version = 2 Record Source = A Type = 1 # Input Checkpoints = 1 # Output Checkpoints = 0File Information: Block Size = 2048 Max Blocks = 100 Record Length = 2048 Current Offset = 0Configuration: Data Source = 0 Transaction Integrity = -1 Task Type = 0Database Checkpoint: Checkpoint table = ggs.checkpoint Key = 982417365 (0x3a8e7fd5) Create Time = 2014-12-27 10:46:19Status: 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 REPLICAT REP1 Last Started 2014-12-27 14:07 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:08 ago)Process ID 26088Log Read Checkpoint File /us01/zt/dirdat/lt000004 2014-12-27 16:49:03.408880 RBA 1755----------------------------------------------------------------------停的时候确保两边都事物都提交了。 info 一下看看 ②. data dump进程：将队列数据发送到目标 好处：① .预防网络和源库的故障； ②. 可以对数据进行过来和转换； ③.synchronize方式从多个源库上合并数据到一个中心库； ④. synchronize方式将一个源库数据传到多个目标库;转：http://blog.csdn.net/zhengwei125/article/details/46503403
