This blog discusses when you would use the COMPRESSUPDATES or COMPRESSDELETES configurations in Oracle GoldenGate.
- COMPRESSUPDATES, the default, causes Extract to write the primary key, the columns in the KEYCOLS, and the changed columns of a row to the trail for update operations. This provides enough information to update the correct target record (unless conflict resolution is required) while restricting the amount of data that must be processed.
- NOCOMPRESSUPDATES sends all of the columns to the trail. This becomes the default when a table definition does not include a primary key or unique index. NOCOMPRESSUPDATES also is required when using the Conflict Detection and Resolution (CDR) feature for a DB2 database on any of the platforms that are supported by Oracle GoldenGate.
Best Practices
You would be cautious when using NOCOMPRESSUPDATES in Oracle GoldenGate because if you have tables with a lot of columns (e.g., 200 columns), this configuration will significantly increase the trail file size and thus impact the replication performance. If you don't have the proper key or unique indexes on the source database, you can consider using the KEYCOLS.
You would be cautious when using NOCOMPRESSUPDATES in Oracle GoldenGate because if you have tables with a lot of columns (e.g., 200 columns), this configuration will significantly increase the trail file size and thus impact the replication performance. If you don't have the proper key or unique indexes on the source database, you can consider using the KEYCOLS.
The similar applies to the COMPRESSDELETES. The supported databases are DB2 LUW, DB2 z/OS, Teradata version 12 or later, SQL Server, and Sybase. Note that this doesn't support for MySQL database.
(Created: 11/25/2013, Last Updated: 10/16/2017)
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