This section discusses space requirements for the Teradata TPump log table.
- One row is written at initialization.
- One row is written for each SQL statement issued through the Teradata TPump support environment.
- One row is written at the BEGIN LOAD command.
- One row is written at the END LOAD command.
- Two rows are written for each IMPORT command.
- One row is written for each statement used in a load (between the BEGIN LOAD command and the END LOAD command).
- One row is written for each checkpoint taken.
- In the ROBUST mode, for each packed request, a number of partial checkpoint rows are written to the log between checkpoints. The rows are deleted each time a checkpoint is written.
The partial checkpoint row contains 117 + (12 * packfactor) bytes per transaction. So the number of partial checkpoints will vary, depending on the checkpoint frequency, the power of the loading host, and the power of the Teradata target database.
Thus, an equation for the space is:
200 + 200 * each statement in the support environment + 400 * each BEGIN/END LOAD + 200 * each statement issued as DML + 200 * the estimated number of checkpoints + (117 + (12 * packfactor)) * the number of partial checkpoints. A simplified version would be:
R = 200 + 200S + 400L + 200D+ 200C + (117 + (12P))N,
where the following is true:
R = Required space for Teradata TPump log table
S = Each SQL statement issued through the support environment
L = Each BEGIN/END LOAD command pair
D = Each DML statement
C = Estimated number of checkpoints
P = Packfactor
N = Number of partial checkpoints