10.1.2 Operation modes of the rebalancing utility

Table 10-1 shows the operation modes of the rebalancing utility.

Table 10-1 Operation modes of the rebalancing utility

Operation modeDescription
Shared modeAccesses to the table are permitted during execution of pdrbal. Use this mode for a system that cannot stop online applications due to 24-hour operation.
Exclusive modeAccesses to the table are not permitted during execution of pdrbal. Use this mode for a system that can deny access to the table and execute batch processing at night.
Organization of this subsection
(1) Shared mode
(2) Exclusive mode

(1) Shared mode

In the shared mode, a table being rebalanced is accessible. To execute the utility in the shared mode, specify share in the -k option.

The shared mode requires acquisition of log information as well as repeated allocation and release of the resources that are required by concurrently executing SQL. Therefore, the time required for a rebalance operation in the shared mode is longer than in the exclusive mode.

Recommended operation method
When executing the rebalancing utility in the shared mode, you should choose a period of time with little traffic on the rebalancing table. Figure 10-3 shows an example of rebalancing utility execution in the shared mode.

Figure 10-3 Example of rebalancing utility execution in shared mode

[Figure]

(2) Exclusive mode

In the exclusive mode, no access is allowed to a table being processed by the rebalancing utility. To execute the rebalancing utility in the exclusive mode, specify exclusive in the -k option.

In the exclusive mode, acquisition of log information is optional. The required resources are allocated and released only once, and batch index creation is permitted; therefore, the time required for the rebalancing operation is less than in the shared mode.

Recommended operation method
When executing the rebalancing utility in the shared mode, you should choose a period of time during which the rebalancing table is not accessed. Figure 10-4 shows an example of rebalancing utility execution in the exclusive mode.

Figure 10-4 Example of rebalancing utility execution in exclusive mode

[Figure]