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Oracle GoldenGate Tutorial 5 – configuring online change synchronization

  • Posted by Gavin Soorma
  • On February 17, 2010
  • 13 Comments
  • change synchronization, GoldenGate, online extract, online replicat

In our earlier tutorial, we examined how to create a GoldenGate environment for initial data capture and load.

In this tutorial, we will see how by using GoldenGate change synchronization, changes that occur on the source (Oracle 11g on Linux) are applied near real time on the target (Oracle 11g on AIX). The table on the source is the EMP table in SCOTT schema which is being replicated to the EMP table in the target database SH schema.

These are the steps that we will take:

Create a GoldenGate Checkpoint table
Create an Extract group
Create a parameter file for the online Extract group
Create a Trail
Create a Replicat group
Create a parameter file for the online Replicat group

Create the GoldenGate Checkpoint table

GoldenGate maintains its own Checkpoints which is a known position in the trail file from where the Replicat process will start processing after any kind of error or shutdown. This ensures data integrity and a record of these checkpoints is either maintained in files stored on disk or table in the database which is the preferred option.

We can also create a single Checkpoint table which can used by all Replicat groups from the single or many GoldenGate instances.

In one of the earlier tutorials we had created the GLOBALS file. We now need to edit that GLOBALS file and add an entry for CHECKPOINTTABLE which will include the checkpoint table name which will be available to all Replicat processes via the EDIT PARAMS command.

GGSCI (devu007) 2> EDIT PARAMS ./GLOBALS

GGSCHEMA GGS_OWNER
CHECKPOINTTABLE GGS_OWNER.CHKPTAB

GGSCI (devu007) 4> DBLOGIN USERID ggs_owner, PASSWORD ggs_owner
Successfully logged into database.

GGSCI (devu007) 6> ADD CHECKPOINTTABLE GGS_OWNER.CHKPTAB

Successfully created checkpoint table GGS_OWNER.CHKPTAB.

apex:/u01/oracle/software/goldengate> sqlplus ggs_owner/ggs_owner

SQL*Plus: Release 11.1.0.6.0 - Production on Mon Feb 8 09:02:19 2010

Copyright (c) 1982, 2007, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> desc chkptab

Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 GROUP_NAME                                NOT NULL VARCHAR2(8)
 GROUP_KEY                                 NOT NULL NUMBER(19)
 SEQNO                                              NUMBER(10)
 RBA                                       NOT NULL NUMBER(19)
 AUDIT_TS                                           VARCHAR2(29)
 CREATE_TS                                 NOT NULL DATE
 LAST_UPDATE_TS                            NOT NULL DATE
 CURRENT_DIR                               NOT NULL VARCHAR2(255)

Create the Online Extract Group

GGSCI (redhat346.localdomain) 1> ADD EXTRACT ext1, TRANLOG, BEGIN NOW
EXTRACT added.

Create the Trail

We now create a trail – note that this path pertains to the GoldenGate software location on the target system and this is where the trail files will be created having a prefix ‘rt’ which will be used by the Replicat process also running on the target system

GGSCI (redhat346.localdomain) 2> ADD RMTTRAIL /u01/oracle/software/goldengate/dirdat/rt, EXTRACT ext1
RMTTRAIL added.

Create a parameter file for the online Extract group ext1

GGSCI (redhat346.localdomain) 3> EDIT PARAMS ext1

EXTRACT ext1
USERID ggs_owner, PASSWORD ggs_owner
RMTHOST devu007, MGRPORT 7809
RMTTRAIL /u01/oracle/software/goldengate/dirdat/rt
TABLE scott.emp;

ON TARGET SYSTEM

Create the online Replicat group

GGSCI (devu007) 7> ADD REPLICAT rep1, EXTTRAIL /u01/oracle/software/goldengate/dirdat/rt
REPLICAT added.

Note that the EXTTRAIL location which is on the target local system conforms to the RMTTRAIL parameter which we used when we created the parameter file for the extract process on the source system.

Create a parameter file for the online Replicat group, rep1

GGSCI (devu007) 8> EDIT PARAMS rep1

REPLICAT rep1
ASSUMETARGETDEFS
USERID ggs_owner, PASSWORD ggs_owner
MAP scott.emp, TARGET sh.emp;

ON SOURCE

Start the Extract process

GGSCI (redhat346.localdomain) 16> START EXTRACT ext1

Sending START request to MANAGER …
EXTRACT EXT1 starting

GGSCI (redhat346.localdomain) 17> STATUS EXTRACT ext1
EXTRACT EXT1: RUNNING

GGSCI (redhat346.localdomain) 16> INFO EXTRACT ext1

EXTRACT EXT1 Last Started 2010-02-08 14:27 Status RUNNING
Checkpoint Lag 00:00:00 (updated 00:00:09 ago)
Log Read Checkpoint Oracle Redo Logs
2010-02-08 14:27:48 Seqno 145, RBA 724480

ON TARGET

Start the Replicat process

GGSCI (devu007) 1> START REPLICAT rep1
Sending START request to MANAGER …
REPLICAT REP1 starting

GGSCI (devu007) 2> INFO REPLICAT rep1

REPLICAT REP1 Last Started 2010-02-08 14:55 Status RUNNING
Checkpoint Lag 00:00:00 (updated 00:00:01 ago)
Log Read Checkpoint File /u01/oracle/software/goldengate/dirdat/rt000001
2010-02-08 14:27:57.600425 RBA 1045

Note: the trail file has a prefix of ‘rt’ (which we had defined earlier)

LET US NOW TEST …

ON SOURCE

SQL> conn scott/tiger
Connected.

SQL> UPDATE emp SET sal=9999 WHERE ename=’KING’;

1 row updated.

SQL> COMMIT;

Commit complete.

ON TARGET

SQL> SELECT SAL FROM emp WHERE ename=’KING’;

SAL
———-
9999

Coming Next! – configuring GoldenGate Data Pump …..

 4

13 Comments

Shabbir
  • Apr 5 2010
Can we extract from physical standy, to avoid load on primary server?
Kamal
  • Jun 3 2010
Hi Gavin, When i start a replicat process for online synchronisation it abends with the following error GGS ERROR 101 Oracle GoldenGate Delivery for Oracle, EMP_REP.prm: Invalid option for MAP: . I am trying to synchronize two tables(with same structure) of same database(Oracle) but different schemas. Some you please solve this for me. Thanks, Kamal
Kamal
  • Jun 3 2010
Hi, Solved the problem. The error was due to a space missing between the comma (,) and TARGET (keyword) in the Replicat params file. eg: my params had MAP sourcetable,TARGET targettable; instead of MAP sourcetable, TARGET targettable; Thanks, Kamal
Gavin Soorma
  • Jun 27 2010
Hi Philip - I think what you can do is that you can create a materialized view based on the records you want from the source table 1 and table 2 and use this MV to push records to table 3 in the target database - GGate allows column transformations and column mapping, but I think the mapping is from one source table to one target table - not sure if you can do mapping where you say I want column a and b from table 1 and column c and d from table 2 to become 4 columns in target table 3 ....
Manju
  • Sep 2 2010
Hi gavin , i was trying to install Goldengate 10.4 on IBM AIX 5.3 powerssytem after tar ing the files when i try to run ggsci i get below errors Could not load program ggsci: Symbol resolution failed for ggsci because: Symbol _GetCatName__FiPCc (number 159) is not exported from dependent module /usr/lib/libC.a[ansi_64.o]. Symbol __ct__Q2_3std8_LocinfoFPCci (number 184) is not exported from dependent module /usr/lib/libC.a[ansi_64.o]. Examine .loader section symbols with the 'dump -Tv' command. please let me know solutions if you have come across this kind of problem
Gavin Soorma
  • Sep 22 2010
Before launching ggsci, check your environment - LD_LIBRARY_PATH and LIBPATH - it should point to $ORACLE_HOME/lib
Raghu
  • Oct 28 2010
Hi Gavin, Your explanation are really good. I have a small confusion that we can implement the Golden Gate other than Oracle Databases. Then how can it recognize the transactions of someother db. I have read that trail file will be i UDF(Universal Data Fomat). How this really works. If possible can u please post the sample trail file Thanks in advance for ur suggestions Raghu
Gavin Soorma
  • Oct 29 2010
Hi Raghu - the Golden Gate extract process writes to a trail file which is stored on the OS file system in proprietory format which can be read only by Goldengate - the trail file is the same as far as Golden Gate is concerned whether the source database is 9i or 10g or 11g or even some other RDBMS like DB2 or Sybase. The same trail file is then read by the GoldenGate replicat process and it does not matter to it what was the source database from where the trail file came from - it just reads the trail file. I am not sure what your doubt is - but Goldengate is available for most main RDBMS types other than just Oracle
Antony
  • Jan 29 2011
Gavin..i was working on this tool for 5-6 years..in various capacities as tech support/consulting etc etc...after reading the tutorials ...i can say you did an excellant job...and you have a great heart to share the knowledge and help others ...i salute that spirit -Antony
GG
  • Feb 9 2011
Hi, Is there any way to specify timewise asynchronize replication. Like 15 mins/hour replication? Thanks
Terry Alexander
  • Mar 8 2011
Gavin, Your a star. Your examples are very good. I have been trying to follow the examples in a book I bought. There have been a few problems with the examples in the book. But your's are spot on thanks Gavin. Cheers, Terry
neerudba
  • Mar 11 2011
Hi I have a Primary environment which is a 2 node rac environment and secondary environment which is a single node environment I have successfully tested replication of SCHEMA from Production environment to Secondary environment However the following scenario is where i would request your expert advise and guidance if we have to do any testing , we shut down the primary server , then perform the testing on the seconary server ( which is in sync due to the goldengate replication ) after we have verified that the testing is successfully we know want to replicate this back on the primary environment Under this circumstance the one option is that after the testing is complete , copy the secndary database to prmary server nd recreate the rac enviroment and release to the users however doing this is very time consuming for us in our environment under this scenario is there an easier option in which we can configure goldengate to sync up the changes from secondary back to primary after the testing is complete Thanks a lot , looking forward to your comments
Arun Upadhyay
  • Apr 7 2017
Thank you !!!

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