1. Oracle GoldenGate Classic Documentation
  2. Prepare
  3. Prepare Your Database for Oracle GoldenGate Classic Architecture
  4. Db2 LUW
  5. Preparing Tables for Processing
  6. Ensuring Row Uniqueness for Tables
  7. How Oracle GoldenGate Determines the Kind of Row Identifier to Use

How Oracle GoldenGate Determines the Kind of Row Identifier to Use

Unless a KEYCOLS clause is used in the TABLE or MAP statement, Oracle GoldenGate selects a row identifier to use in the following order of priority:

  1. Primary key

  2. First unique key alphanumerically that does not contain a timestamp or non-materialized computed column.

  3. If none of the preceding key types exist (even though there might be other types of keys defined on the table) Oracle GoldenGate constructs a pseudo key of all columns that the database allows to be used in a unique key, excluding those that are not supported by Oracle GoldenGate in a key or those that are excluded from the Oracle GoldenGate configuration.

Note:

If there are other, non-usable keys on a table or if there are no keys at all on the table, Oracle GoldenGate logs an appropriate message to the report file. Constructing a key from all of the columns impedes the performance of Oracle GoldenGate on the source system. On the target, this key causes Replicat to use a larger, less efficient WHERE clause.