Load a few tables in Target when replication is running and then re-sync them with Source

Owned by Clive Otten (Unlicensed)
Jan 21, 2020

This article explains the procedure on how to sync the tables in Source, after a few tables have had data loaded into the Target. This is similar to a DR DRILL in which the application is re-directed to the Target during which time a few tables are populated and subsequently these changes have to be 're-sync'd' with the Source

 

Problem Details

Problem Statement

Sync tables in source when the tables are loaded in target

Applicable Error Code

N/A

Affected Versions

Tested in 2.8 and 2.9

Affected Platforms

Platform Independent

 

Description

 The example used here is a sample replication environment, Below are the high level steps that are performed for this activity. 

  1. Mine and Apply Process is running.

  2. Unprepare the tables which would be affected in target.

  3. Load data in target /Test application in target.

  4. Truncate table in source.

  5. Load the affected table from target(using expdp/impdp)

  6. prepare the table again.

  7. Test a data load in source to see if target is getting replicated.

Steps Performed

  1. MINE and APPLY Process is running.

\ Dbvisit Replicate 2.9.00(MAX edition) - Evaluation License expires in 30 days MINE is running. Currently at plog 1090 and SCN 15067569 (06/29/2017 14:09:30). APPLY is running. Currently at plog 1090 and SCN 15067539 (06/29/2017 14:09:16). Progress of replication TEST:MINE->APPLY: total/this execution -------------------------------------------------------------------------------------------------------------------------------------------- VIJAY.EMP: 100% Mine:100/100 Unrecov:0/0 Applied:100/100 Conflicts:0/0 Last:29/06/2017 14:07:04/OK VIJAY.DEPT: 100% Mine:10/10 Unrecov:0/0 Applied:10/10 Conflicts:0/0 Last:29/06/2017 14:07:10/OK -------------------------------------------------------------------------------------------------------------------------------------------- 2 tables listed.

  1. Unprepare the tables which would be affected in the target(In this example we are just using one table)

dbvrep> unprepare table vijay.emp Connecting to running mine [VIJAY.EMP]: [Table unprepared (1 internal records).] Connecting to running apply:[Apply table removed (1 metadata record(s)). Apply table added (0 metadata record(s)).] Table VIJAY.EMP processed. dbvrep>

  1. Load data in Target/Test Application in target(In this example we are just loading 1000rows for table EMP in target

Target: SQL> exec gen_data('EMP',1000); PL/SQL procedure successfully completed. SQL> select count(*) from emp; COUNT(*) ---------- 1114

  1. Truncate the table in Source

  1. Export the table in target

  1. Import in Source

  1. Prepare the table again in replication

  1. Load data in source to check if replication is catching up

Conclusion

We highly recommend to perform these steps in a test environment before trying in the live production environment, If any of the steps are missed , you might have to instantiate the entire replication again after reloading the source environment with the latest data.