If a target table does not have a primary key, a unique key, or a unique index, Replicat uses all of the columns to build its WHERE clause. This is, essentially, a full table scan.

To make row selection more efficient, use a KEYCOLS clause in the TABLE and MAP statements to identify one or more columns as unique. Replicat will use the specified columns as a key. The following example shows a KEYCOLS clause in a TABLE statement:

TABLE hr.emp, KEYCOLS (FIRST_NAME, LAST_NAME, DOB, ID_NO);

For usage guidelines and syntax, see the TABLE and MAP parameters in Parameters and Functions Reference for Oracle GoldenGate.