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Input sources for apply requests

This section describes the SQL and logical log input sources that High-speed Apply Engine uses.

For more information about specifying the input sources in a configuration or an apply request, see Defining configurations or Using.

SQL statements

You can specify an input file that contains SQL statements.

The SQL can be generated by the following sources:

  • Log Master for DB2

  • Other standard SQL generators

SQL input can include data manipulation language (DML) or data definition language (DDL) statements. High-speed Apply Engine can process any DML or DDL statements that are accepted by the target DBMS. To provide restart capability, High-speed Apply Engine requires that SQL input does not contain more than one SQL statement on the same line.

The Log Master for DB2 product generates a separate template file that High-speed Apply Engine can use to efficiently process SQL input as static SQL against DB2 for mainframe targets or DB2 LUW targets. The template file contains one entry for each distinct statement type in the SQL input. If an apply request includes a template file, High-speed Apply Engine processes the template file before it begins processing SQL input.

Logical log

The High-speed Apply Engine running on mainframe operating systems accepts logical logs as an input source. Log Master for DB2 produces logical logs that let you specify the types of operations that you need to perform. The logical log files provide information that High-speed Apply Engine can use to update the target tables.

Logical log input consists of the following files:

  • The logical log control file contains information about the format and content of the logical log. Specify the control file as the input for High-speed Apply Engine.

  • The logical log data file contains actual change information (updates, deletes, inserts, or DDL objects) in logical log format.

  • (optional) The large volume VSAM files contain data from DB2 columns that hold large volumes of data (such as XML columns or LOB columns). To apply changes to large volume columns, the appropriate VSAM files must be available to High-speed Apply Engine along with the control file and the data file.

  • (optional) The logical log XMLSTRING control file contains the string IDs and string data that DB2 uses to encode the data in XML columns. If the logical log includes XML data and the target DB2 subsystem is different than the subsystem where the logical log was generated, High-speed Apply Engine needs the string IDs and data to serialize your XML data correctly.

High-speed Apply Engine can often process a logical log file faster than an SQL file that contains the same database changes. This improvement occurs because logical log input is already in host variable format. High-speed Apply Engine can also avoid parsing SQL syntax.

You can create logical logs to perform data migration, UNDO SQL functions, or REDO SQL functions. For more information on the logical log records that High-speed Apply Engine uses, see Logical log input. For more information about logical logs, see  Log Master for DB2 documentation .

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