单实例数据库多日志线程，搭建ogg,启动抽取进程时提示一下错误：
ERROR OGG-00446 Oracle GoldenGate Capture for Oracle, extjms.prm: The number of Oracle redo threads (2) is not the same as the number of checkpoint threads (1). EXTRACT groups on RAC systems should be created with the THREADS parameter (e.g., ADD EXT <group name>, TRANLOG, THREADS 2, BEGIN…).
BECAUSE:which GoldenGate thread number corresponds to the Oracle redo threads, use the output from v$log,my oracle have two redo threads and goldengate configue one extract group;
解决有两种：
一、删除oracle日志线程2
SQL> alter database disable thread 2;
Database altered.
SQL> alter database drop logfile group 3;
Database altered.
SQL> alter database drop logfile group 4;
Database altered.
二、增加线程2的抽取进程
GGSCI (host01) > Add Extract extjms2, TranLog,threads 2, Begin Now
GGSCI (host01) > Add ExtTrail ./dirdat/js, Extract extjms, Megabytes 50
