Oracle GoldenGate Processes – Part 2 – Extract

The extract process of Oracle GoldenGate is used to perform change data capture from the source database.  The extract can be used to read the online transaction log (in Oracle the online redo logs) or the associated archive logs.  The data that is extracted from the source database is then placed into an trail file (another topic for a post) for shipping to the apply sided. 

To configure an extract process there needs to be a parameter file associated with it.  The parameter file can be edited after adding the extract to the Oracle GoldenGate environment if needed.  In order to configure an extract it needs to be added to the environment and assigned a local trail file location.

Adding an Extract and Local Trail File:

Using GGSCI:

$ cd $OGG_HOME
$ ./ggsci
GGSCI> add extract EXT, tranlog, begin now
GGSCI> add exttrail ./dirdat/lt, extract EXT, megabytes 200

Note: The trail file is required to be prefixed with a two letter prefix.  

Edit Extract Parameter File:

From GGSCI:

$ cd $OGG_HOME
$ ./ggsci
GGSCI> edit params EXT

Edit Extract Parameter File from Command Line:

$ cd $OGG_HOME
$ cd ./dirprm
$ vi ./ext.prm

Example of Extract Parameter File:

EXTRACT EXT
USERID ggate, PASSWORD ggate 
TRANLOGOPTIONS DBLOGREADER
SETENV (ORACLE_HOME=”/u01/app/oracle/product/11.2.0/db_3″)
SETENV (ORACLE_SID=”orcl”)
WARNLONGTRANS 1h, CHECKINTERVAL 30m
EXTTRAIL ./dirdat/lt
WILDCARDRESOLVE IMMEDIATE
TABLE SCOTT.*;

Start/Stop the Extract:

Start Extract:

$ cd $OGG_HOME
$ ./ggsci
GGSCI> start extract EXT

Stop Extract:

$ cd $OGG_HOME
$ ./ggsci
GGSCI> stop extract EXT

Enjoy!

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