This section explains how the Capture program handles warm starts, how it switches to an automatic cold start, and when you might want to force a warm start.
When you start the Capture program with the WARM or WARMNS parameter, it searches for the ASN.IBMSNAP_WARM_START table, which is created either during the first definition of a registration source or when DPCNTL.* is executed. This table contains information that enables the Capture program to quickly resynchronize to the time when it stopped. If this table is not available, the Capture program can resynchronize using either the register table, UOW table, or change data tables.
Warm start information is saved in most cases. In extreme cases, warm start information might not be saved. For example, an operator might cancel the Capture program or stop DB2. In this case, the Capture program uses the change data, UOW, or register table to resynchronize to the time it was stopped.
After a successful warm start, the old rows in the warm start table are deleted.
The Capture program switches to a cold start if you did not specify WARMNS and the warm start log sequence number is not available in the log. The Apply program performs a full refresh after a cold start.
For information about handling gap messages, see Problems Using the Apply Program and read the section about forcing the Apply program to perform a full refresh.)
Sometimes the Capture program automatically switches to a cold start, even when you specify a warm start. The switch is made when:
The first time that you invoke the Capture program, you see message ASN0102W, indicating that the warm start failed. The Capture program switches to a cold start. You can ignore this message when first invoking the Capture program.
For each of these cases, the Capture program issues an informational message and performs a cold start.
You might want to prevent the Capture program from cold starting in some situations. For instance, the Capture program cold starts if DB2 goes down, or if someone brings down the DB2 table space containing the change data table. Forcing a warm start with the WARMNS parameter ensures that the control tables remain intact. You must correct the problem that caused the Capture program to terminate. If you do not correct the problem, the Capture program continues to terminate every time you start it.