Extract Generates A large Volume of Trail Data For Lob Updates On Oracle
Applies to:
Oracle GoldenGate - Version: 10.4.0.0 and later [Release: 10.4.0 and later ]
Information in this document applies to any platform.
Symptoms
Some examples of excessive trails generation are :-
Generated 8.8GB of trail when redo log was only generated ~ 20MB,
Generated 100GB of Trail for a 245mb update.
When you look at the logminer log miner shows the following repeating over and over.
SEL_LOB_LOCATOR 08/21/10 12:57:37 TABLE FM_COV_LIST
LOB_WRITE 08/21/10 12:57:37 TABLE FM_COV_LIST
LOB_WRITE 08/21/10 12:57:37 TABLE FM_COV_LIST
INTERNAL 08/21/10 12:57:37 TABLE FM_COV_LIST
INTERNAL 08/21/10 12:57:37 TABLE FM_COV_LIST
SEL_LOB_LOCATOR 08/21/10 12:57:37 TABLE FM_COV_LIST
LOB_WRITE 08/21/10 12:57:37 TABLE FM_COV_LIST
LOB_WRITE 08/21/10 12:57:37 TABLE FM_COV_LIST
INTERNAL 08/21/10 12:57:37 TABLE FM_COV_LIST
INTERNAL 08/21/10 12:57:37 TABLE FM_COV_LIST
INTERNAL 08/21/10 12:57:37 TABLE FM_COV_LIST
Cause
GoldenGate reads these records from the archive log files with the LOB data and writes to trail files which because of the looping of Oracle database package DBMS_LOB.writeappend.
Solution
These updates have been show to be duplicates, Use OGG 10.4.0.19 or better and add the parameter FETCHOPTIONS SUPPRESSDUPLICATES this will suppress these duplicates sending only the last update to the trail.
Extract Generates A large Volume of Trail Data For Lob Updates On Oracle
适用于:
OracleGoldenGate的-版本:10.4.0.0和更高版本:10.4.0和更高版本]
在这个文档中的信息适用于任何平台。
症状
过度径一代的一些例子是:-
线索时只产生重做日志〜20MB8.8GB,
径生成100GB为245mb更新。
当你看的LogMiner日志矿工显示以下重复一遍又一遍。
SEL_LOB_LOCATOR08/21/1012:57:37TABLEFM_COV_LIST
LOB_WRITE08/21/1012:57:37TABLEFM_COV_LIST
LOB_WRITE08/21/1012:57:37TABLEFM_COV_LIST
INTERNAL08/21/1012:57:37TABLEFM_COV_LIST
INTERNAL08/21/1012:57:37TABLEFM_COV_LIST
SEL_LOB_LOCATOR08/21/1012:57:37TABLEFM_COV_LIST
LOB_WRITE08/21/1012:57:37TABLEFM_COV_LIST
LOB_WRITE08/21/1012:57:37TABLEFM_COV_LIST
INTERNAL08/21/1012:57:37TABLEFM_COV_LIST
INTERNAL08/21/1012:57:37TABLEFM_COV_LIST
INTERNAL08/21/1012:57:37TABLEFM_COV_LIST
原因
GoldenGate的读取LOB数据的归档日志文件的这些记录,并写入线索,因为Oracle数据库包DBMS_LOB.writeappend循环文件。
解决方案
这些更新已显示是重复的,使用OGG 10.4.0.19或更好并添加参数FETCHOPTIONS SUPPRESSDUPLICATES这将抑制这些重复发送只有最后一次更新的线索。