10.1.1 Functions of the rebalancing utility

If an RDAREA is added to accommodate new data for a hash-partitioned table, an imbalance of data occurs between the existing RDAREAs and the added RDAREA. The rebalancing utility (pdrbal) is used to correct such a data imbalance. Correcting an imbalance of data in a hash-partitioned table is called the rebalancing facility for hash row partitioning.

The rebalancing utility rearranges data in units of hash groups. This is called table rebalancing. The table partitioned by a hash function (HASHA to HASHF) is called a rebalancing table.

Figure 10-1 shows an overview of the rebalancing utility and Figure 10-2 shows an overview of rebalancing.

Figure 10-1 Overview of the rebalancing utility

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Figure 10-2 Overview of rebalancing

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Explanation:
Start of rebalancing
This is the point at which the first pdrbal is executed after an RDAREA has been added (ALTER TABLE ADD RDAREA) to the rebalancing table.
Rebalancing initialization processing
This is the initialization processing executed at the first execution of pdrbal after an RDAREA has been added.
Rebalancing completion processing
This is the completion processing executed when pdrbal has terminated with return code 0.
End of rebalancing
This is the point at which rebalancing of all table data is completed (pdrbal terminated with return code 0).
Rebalancing
This is a period during which rebalancing is underway.