Splitting a *-Hash Partition

This is the opposite of merging *-hash partitions. When you split *-hash partitions, the new subpartitions are rehashed into either the number of subpartitions specified in a SUBPARTITIONS or SUBPARTITION clause. Or, if no such clause is included, the new partitions inherit the number of subpartitions (and tablespaces) from the partition being split.

The inheritance of properties is different when a *-hash partition is split, versus when two *-hash partitions are merged. When a partition is split, the new partitions can inherit properties from the original partition because there is only one parent. However, when partitions are merged, properties must be inherited from table level defaults because there are two parents and the new partition cannot inherit from either at the expense of the other.

The following example splits a range-hash partition:

ALTER TABLE all_seasons SPLIT PARTITION quarter_1 
     AT (TO_DATE('16-dec-1997','dd-mon-yyyy'))
     INTO (PARTITION q1_1997_1 SUBPARTITIONS 4 STORE IN (ts1,ts3),
           PARTITION q1_1997­_2);

The rules for splitting an interval-hash partitioned table follow the rules for splitting an interval-partitioned table. As described in "Splitting a Partition of an Interval-Partitioned Table", the transition point is changed to the higher boundary of the split partition.