Load and unload data

You can load data into or unload data out of tables in your replication environment in various ways, depending on your circumstances.

If you have not yet set up your replication environment, for loading data, you can use the following tools:
  • High-Performance Loader
  • onunload and onload Utilities
  • dbexport and dbimport utilities
  • UNLOAD and LOAD statements
  • External tables

When you unload and load data, you must use the same type of utility for both the unload and load operations. For example, you cannot unload data with the onunload utility and then load the data with a LOAD statement.

Existing replication environment

If you are adding a table to your already existing replication environment, Enterprise Replication provides an initial synchronization feature that allows you to easily bring a new table up-to-date with replication. You can synchronize the new table with data on the source server you specify when you start the new replicate, or when you add a new participant to an existing replicate. You do not need to suspend any servers that are replicating data while you add the new replicate and synchronize it.

If you want to use load and unload tools on tables that are already being replicated, you should block replication while you prepare the table. Unlogged changes to a table, such as data added by a light append, can be replicated to other tables.

If a table that you plan to replicate includes the CRCOLS or REPLCHECK shadow columns, the statements that you use for unloading the data must explicitly name the shadow columns. If you use the SELECT statement with * FROM table_name to the data to unload, the data from the shadow columns is not unloaded. To include the shadow columns in the unloaded data, explicitly name them. For example, use a statement like the following: 
SELECT cdrserver, cdrtime, ifx_replcheck, * FROM table_name

If a table that you plan to replicate includes ERKEY shadow columns, you cannot unload and then load the data from these columns and preserve the original values. If you need to preserve the values of the ERKEY shadow columns, use synchronization to propagate the values.