Table of Contents

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  1. Preface
  2. Data Replication Overview
  3. Understanding Data Replication
  4. Sources - Preparation and Replication Considerations
  5. Targets - Preparation and Replication Considerations
  6. Starting the Server Manager
  7. Getting Started with the Data Replication Console
  8. Defining and Managing Server Manager Main Servers and Subservers
  9. Creating and Managing User Accounts
  10. Creating and Managing Connections
  11. Creating Replication Configurations
  12. Materializing Targets with InitialSync
  13. Scheduling and Running Replication Tasks
  14. Implementing Advanced Replication Topologies
  15. Monitoring Data Replication
  16. Managing Replication Configurations
  17. Handling Replication Environment Changes and Failures
  18. Troubleshooting
  19. Data Replication Files and Subdirectories
  20. Data Replication Runtime Parameters
  21. Command Line Parameters for Data Replication Components
  22. Updating Configurations in the Replication Configuration CLI
  23. DDL Statements for Manually Creating Recovery Tables
  24. Sample Scripts for Enabling or Disabling SQL Server Change Data Capture
  25. Glossary

Sync Point Value

Sync Point Value

Data Replication stores a Sync Point value in the configuration for each of the mapped target tables. This value indicates the point up to which InitialSync synchronized the target tables with the source tables.
Initially, a configuration specifies -1 as the Sync Point value for all of the mapped tables. This value indicates that initial synchronization has not been completed for the target tables.
When you run InitialSync, it synchronizes the mapped target tables with the source tables for which the Sync Point value is -1. Data Replication then writes an updated Sync Point value to the configuration for each synchronized table, as follows:
  • For Oracle
    and Microsoft SQL Server
    sources, InitialSync retrieves the system change number (SCN)
    or log sequence number (LSN)
    value from the source database for the initial synchronization transaction and writes this value to the configuration for each synchronized table.
  • For MySQL sources, InitialSync retrieves the log coordinates from the source database for the initial synchronization. InitialSync writes this value to the configuration for each synchronized table.
  • For DB2 for Linux, UNIX, and Windows sources, InitialSync adds records to the service table, which is named DBSYNC_SYNC_LSN by default, for each synchronized table. When you run the Extractor later, it uses these records to determine the LSN value of the source database up to which the target tables are synchronized with the source tables. The Extractor writes this value to the configuration for each synchronized table.
In the Data Replication Console, you can manually edit the Sync Point value that is stored in a configuration for a mapped table. You might need to edit the Sync Point value for a particular table under the following circumstances:
  • You need to resynchronize a target table that was previously synchronized. For example, InitialSync ended abnormally. In this case, you need to truncate the table, set its Sync Point value to -1, and then run InitialSync again.
  • You want to skip the InitialSync task and configure the Applier to start change data replication for a table from a specific point in the logs. For example, if you use a third-party utility to synchronize target tables, you can set the Sync Point value to the SCN
    , log coordinates,
    or LSN that corresponds to the point from which you want to start change data replication.

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