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 warm start table, ASN.IBMSNAP_WARM_START, which is created 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 the warm start table is empty, the Capture program can resynchronize using either the register table ASN.IBMSNAP_REGISTER, UOW table, or CD 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 CD, UOW, or register tables 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 DB2 3.1 active log, or if it is not available in the DB2 for OS/390 active or archived logs. The Apply program performs a full refresh after a cold start. You can use the technique described in Loading the Tables within a Subscription Set instead of having the Apply program perform the LOADX of the target table.
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.
In 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 tablespace containing the CD 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 or perform a cold start every time you start it.