Reference for Oracle GoldenGate

Valid For

Extract

Description

Use the COMPRESSDELETES and NOCOMPRESSDELETES parameters to control the way that columns are written to the trail record for DELETE operations.

COMPRESSDELETES and NOCOMPRESSDELETES can be used globally for all TABLE statements in the parameter file, or they can be used as on-off switches for individual TABLE statements.

These parameters support the following databases:

Oracle
DB2 LUW
DB2 z/OS
DB2 for i
MySQL
SQL Server
PostgreSQL

Default

COMPRESSDELETES

Syntax

{COMPRESSDELETES | NOCOMPRESSDELETES [FETCHMISSINGCOLUMNS]}

COMPRESSDELETES

Causes Extract to write only the primary key to the trail for DELETE operations. This is the default. The key provides enough information to delete the correct target record, while restricting the amount of data that must be processed.

NOCOMPRESSDELETES [FETCHMISSINGCOLUMNS]

NOCOMPRESSDELETES sends all the columns to the trail. This becomes the default when a table definition does not include a primary key or unique index, or when a substitute key is defined with the KEYCOLS option of TABLE. The KEYCOLS option writes the specified columns to the trail whether or not a real key exists. See KEYCOLS (columns) for more information about the KEYCOLS option.

For SQL Server, columns of IMAGE, NTEXT, and TEXT data types are written as NULL values for delete operations. For more information regarding this restriction, review the Large Object Data Types content at the following Microsoft document:

https://docs.microsoft.com/en-us/sql/relational-databases/system-tables/cdc-capture-instance-ct-transact-sql?view=sql-server-ver15

NOCOMPRESSDELETES is also required when using the Conflict Detection and Resolution (CDR) feature. See Administering Oracle GoldenGate and About Automatic Conflict Detection and Resolution in Using Oracle GoldenGate for Oracle Database for more information about CDR.

FETCHMISSINGCOLUMNS is valid for Oracle Database only. It causes the values of data types that are only supported by fetching to be fetched from the database on DELETE operations. These data types are LOB, UDT, LONG, and some XMLType columns. For detailed information about columns that are supported by fetching (rather than directly captured from the redo stream), see Configuring a Downstream Mining Database in Using Oracle GoldenGate for Oracle Database. The columns that are fetched will appear in the trail file as part of the DELETE record. If NOCOMPRESSDELETES is used for Oracle Database data without the FETCHMISSINGCOLUMNS option, only the LOB data that can be read from the logs (without fetching) will be included in the DELETE operation in the trail.