OGG 11g Checkpoint 詳解
2024-07-21 02:52:52
供稿：網友
OGG Checkpoint 詳解定位中斷的位置，下次啟動從中斷的位置開始恢復。1.target 端配置；2.一條記錄對應一個replicat一. Extract Checkpoints (1) Extract read checkpoints （1） Startup checkpoint --ogg啟動的時候創建 當Extract 進程啟動的時候，會創建startup checkpoint，用來記錄此時record的相關信息。該 checkpoint 是第一個checkpoint。 startup checkpoint的統計信息包含如下內容： （1） Thread #: 創建checkpoint 的thread編號。 （2） Sequence #:創建checkpoint 時對應的sequence 號碼。 --list archive log; （3） RBA: 創建checkpoint 時，redo log 里面record 的relative byte address。 （4）Timestamp: 創建checkpoint 時record對應的timestamp。 （5）SCN: 創建checkpoint 時 record 對應的system change number 。 （6）Redo File: 創建checkpoint 時record對應的事務日志路徑。 2 ) Recovery checkpoint recover checkpoint 記錄的是data source（online redo log 或者歸檔中）中Extract 最久沒處理的record的位置。 該checkpoint 的統計信息和startup checkpoint一樣。3) Current checkpointcurrent checkpoint 是data source中Extract 最后一次讀取的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 會變，說明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該checkpoint包含如下信息：（1）Sequence #: checkpoint 正在寫的trail 文件的序列號。（2）RBA: 創建checkpoint 時trail文件里record 的relative byte address。（3）Timestamp: 創建checkpoint 時record對應的timestamp。（4）Extract trail: trail 文件的路徑。（5）Trail Type: 標識trail 文件類型。有2個值：EXTTRAIL：表示該trail 是本地的trail，文件由OGG進程直接寫如本地disk。RMTTRAIL：表示是遠程的trail，該文件不會寫入本地的磁盤，而是傳到遠端的的OGG上，在有遠端OGG的collector 進程寫disk。 比如pump 進程，里面就會寫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): --最后一次讀取文件的位置 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是否有變化 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----------------------------------------------------------------------停的時候確保兩邊都事物都提交了。 info 一下看看 ②. data dump進程：將隊列數據發送到目標 好處：① .預防網絡和源庫的故障； ②. 可以對數據進行過來和轉換； ③.synchronize方式從多個源庫上合并數據到一個中心庫； ④. synchronize方式將一個源庫數據傳到多個目標庫;轉：http://blog.csdn.net/zhengwei125/article/details/46503403
