Valid Code Combinations in the Checkpoint Template File
The valid code combinations in the checkpoint template file are shown here:
B [S,R,E,J,U] [T,D,E] [T,D,E,A]
P [S,R] [T,D] [D,T]
W [S,R,E,J,U,D,C] [T,D,E] [T,D,E,A]
I [,R,E] [T,D,E] [T,E]
F [,R,E] [T,D,E] [T,E]
E [S,E] [T,D] [D,T,E]
For every entry with a first character of B, there must be an accompanying entry beginning with E.
This section demonstrates how the codes are used in the checkpoint template file to perform checkpointing and roll forward operations in a variety of ways.
Checkpointing
The checkpointing operation (ckpdb command) executes the following sequence of codes in the cktmpl.def file:
Bsxy Beginning checkpoint
Wsxy Executed once for each location
Esxy Ending checkpoint
where:
x denotes D for disk, T for tape, or E for both.
y denotes D for database, T for table, or E for both.
Roll Forward
The roll forward operation (rollforwarddb command) processes the following codes in the cktmpl.file:
WCxA for each location
If table processing is specified, the following codes are executed:
BRxT once per location
IRxT once per location
WDxT for each table
WRxT for each table
FRxT once per location
EExE once (note that ERxT is executed if available)
If an entire database is being recovered (rather than specific tables), the following codes are executed:
BRxD once for each location
WDxD once for each location
WRxD once for each location
EExE once (note that ERxD is executed if available)
For all roll forward operations, the following codes are executed:
BUxA if dumps are to be applied
WUxA
EExE
BJxA if journals are to be applied
WJxA
EExE