最近有几项业务下线，需要从一张表中删除6.8亿多条数据。想办法把数据删除掉了，但对应的ogg灾备端复制时有了的延迟，而且延迟的时间起来越长。
对于表太多造成的延迟可以把所有表分为多个组来做复制，于是想复制进程是否可以对单表复制开并行。上网查到了相关的资料，可以使用@RANGE函数对单表作表内的拆分，通过对表上主键列作hash算法将该表上发生的变更均分到多个replicat上来降低单个replicat组件的负载。
动手实验一下：
ogg搭建过程不再重复，从网上就可以查到。
实验过程：模拟在源端对表scott.emp1做大量的dml操作，复制进程出现延迟，在目标端对复制表scott.emp1开并行3个进程。
源端插入数据：
SQL> insert into scott.emp1 select * from scott.emp;
14 rows created.
SQL> commit;
Commit complete.
SQL> insert into scott.emp1 select * from scott.emp1;
14 rows created.
SQL> /
28 rows created.
SQL> /
.......
SQL> /
1835008 rows created.
SQL> commit;
Commit complete.
SQL> select count(*) from scott.emp1;
COUNT(*)
----------
3670016目标端有延迟
GGSCI (rhel5) 15> info all
Program Status Group Lag Time Since Chkpt
MANAGER RUNNING
REPLICAT RUNNING REPTAB 00:09:08 00:00:04停掉复制进程
拆分复制进程，对表scott.emp1分三个进程复制
#源复制进程
GGSCI (rhel5) 23> view params reptab
replicat reptab
SETENV (NLS_LANG="AMERICAN_AMERICA.ZHS16GBK")
SETENV (ORACLE_SID="orcl")
userid ogg,password 123456
reperror default,discard
assumetargetdefs
discardfile /goldengate/dirrpt/reptab.dsc,append,megabytes 1024
gettruncates
dynamicresolution
map scott.emp1, target scott.emp1 ;
map scott.emp, target scott.emp ;源进程修改为
map scott.emp1, target scott.emp1 ,FILTER(@RANGE(1,3));多复制出两个参数文件：
GGSCI (rhel5) 1> view params reptab02
replicat reptab02
SETENV (NLS_LANG="AMERICAN_AMERICA.ZHS16GBK")
SETENV (ORACLE_SID="orcl")
userid ogg,password 123456
reperror default,discard
assumetargetdefs
discardfile /goldengate/dirrpt/reptab.dsc,append,megabytes 1024
gettruncates
dynamicresolution
map scott.emp1, target scott.emp1 ,FILTER (@RANGE(2,3));
GGSCI (rhel5) 2> view params reptab03
replicat reptab03
SETENV (NLS_LANG="AMERICAN_AMERICA.ZHS16GBK")
SETENV (ORACLE_SID="orcl")
userid ogg,password 123456
reperror default,discard
assumetargetdefs
discardfile /goldengate/dirrpt/reptab.dsc,append,megabytes 1024
gettruncates
dynamicresolution
map scott.emp1, target scott.emp1 ,FILTER (@RANGE(3,3));添加两个复制进程，extseqno和extrba与源进程一致
GGSCI (rhel5) 9> info reptab
REPLICAT REPTAB Last Started 2017-05-05 16:18 Status ABENDED
Checkpoint Lag 00:09:08 (updated 00:09:38 ago)
Log Read Checkpoint File ./dirdat/tl000003
2017-05-05 16:09:11.000187 RBA 194186157
GGSCI (rhel5) 10> add replicat reptab02, exttrail ./dirdat/tl,extseqno 3 extrba 194186157,checkpointtable ogg.checkpoint
REPLICAT added.
GGSCI (rhel5) 11> add replicat reptab03, exttrail ./dirdat/tl,extseqno 3 extrba 194186157,checkpointtable ogg.checkpoint
REPLICAT added.启动复制进程
GGSCI (rhel5) 12> start reptab*
Sending START request to MANAGER ...
REPLICAT REPTAB starting
Sending START request to MANAGER ...
REPLICAT REPTAB02 starting
Sending START request to MANAGER ...
REPLICAT REPTAB03 starting查看数据库里ogg对应的会话
SQL> select module,sql_id from v$session where username='OGG';
MODULE SQL_ID
------------------------------------------------------------------------------------------------------------------------------------------------ ---------------------------------------
OGG-REPTAB03-OPEN_DATA_SOURCE 1cxrusnmn01hz
OGG-REPTAB-OPEN_DATA_SOURCE 1cxrusnmn01hz
OGG-REPTAB02-OPEN_DATA_SOURCE 1cxrusnmn01hz
SQL> select sql_text from v$sqlarea where sql_id='1cxrusnmn01hz';
SQL_TEXT
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
INSERT INTO "SCOTT"."EMP1" ("EMPNO","ENAME","JOB","MGR","HIREDATE","SAL","COMM","DEPTNO") VALUES (:a0,:a1,:a2,:a3,:a4,:a5,:a6,:a7)可以看到出现了三个会话，都是对应的对表scott.emp1的插入语句。也就是说实现了对scott.emp1表的并行复制。
MOS上也有相关的文档介绍相应的功能，文档：1320133.1和1512633.1
参考：blog.itpub.net/15187685/viewspace-1219731/
