The IBMQREP_SIGNAL control table

The IBMQREP_SIGNAL table is a mechanism used to communicate with Q Capture. Remember that Q Capture reads from the DB2 logs, so if we insert data into the IBMQREP_SIGNAL table, then this will be picked up by Q Capture.

Note

The Q Capture does not read the IBMQREP_SIGNAL table, it detects when a row has been inserted into the table by reading the DB2 logs (it is the only control table that has DATA CAPTURE CHANGES set).

The following shows the structure of the IBMQREP_SIGNAL table:

SIGNAL_TIME TS NNWD CURRENT TS
SIGNAL_TYPE VCHAR(30) NOT NULL
SIGNAL_SUBTYPE VCHAR(30)
SIGNAL_INPUT_IN VCHAR(500)
SIGNAL_STATE CHAR(1) NNWD 'P'
SIGNAL_LSN CHAR(10) FOR BIT DATA

Let's look at each column in detail:

• SIGNAL_TIME: Timestamp that is used to uniquely identify the row. Q Capture uses this value to find the correct row in the signal table to indicate when it completed processing the Q Capture signal.

• SIGNAL_TYPE: This is a flag that indicates the type of signal that was posted...