CDC Guide for i5/OS

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Special Override Statement

Use a special override statement to specify a pair of restart tokens or the CURRENT_RESTART option as the restart point for a CDC session.

When you warm start the CDC session, the special override statement overrides the restart tokens in the state table or state file for the session. You can use the special override statement in conjunction with explicit override statements, which pertain to specific sources. In this case, the special override statement sets a restart point for all sources in the CDC session except those for which an explicit override statement is defined.

A special override statement is composed of a pair of RESTART1 and RESTART2 statements. Use the following syntax:

RESTART1={restart1_token|CURRENT_RESTART}
RESTART2={restart2_token|CURRENT_RESTART}

You can specify only one pair of these statements in the restart token file.

For z/OS sources, if you use the default value of Y for the FUZZYRSTART parameter in the LRAP CAPI_CONNECTION statement, you can enter a restart2_token position other than a begin-uow position from which to start extraction processing in the PowerExchange Logger for z/OS logs. In the following example, the restart2_token value points to a RBA position that does not coincide with a begin-uow record and the restart1_token value points to a position before the restart2_token position:

For the restart1_token value, specify

000000000001000000000000000000000000000000000000

. This value consists of 48 zeroes with a "1" in the twelfth position. With this value, the restart2_token value will determine the records to be returned by the extraction.

For the restart2_token value, specify a value that consists of a 6-byte Logger ID in EBCDIC format (padded with spaces) + a 6-byte RBA position + 8 zeroes. The RBA position can be any RBA in the logs near where you want to restart extraction processing. For example:

E2C2F2D340400000000AEF4000000000

With these restart token settings, PowerExchange begins extraction processing at the first record that is at or past the restart1_token position and in the first UOW that is returned based on the restart2_token position.

Parameter descriptions:

restart1_token: The sequence token portion of a restart token pair. This value varies based on data source type.
restart2_token: The restart token portion of a restart token pair. This value varies based on data source type.
CURRENT_RESTART: The option for generating a pair of restart tokens that mark the current end of the change stream. The PWXPC CDC reader opens a separate connection to PowerExchange, requests the generation of current restart tokens, and then provides the token values to all applicable sources.

Optionally, you can generate current restart tokens in the
Database Row Test
dialog box of the PowerExchange Navigator.

Use the CURRENT_RESTART option only for CDC sessions that use real-time extraction mode or continuous extraction mode.

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CDC Guide for i5/OS

CDC Guide for i5/OS

Special Override Statement

Special Override Statement