# Rules for partitioning

When you use partitioning, the logic used for distribution, repartitioning, and buffer allocations will be dependent upon the following rules:

* A partitioned step causes one step copy to be executed per partition in the partition schema.
* When a step needs to repartition the data, the step creates buffers (row sets) from each source step copy to each target step copy (partition).
* When rows of data pass from a non-partitioned step to a partitioned one, data is repartitioned and extra buffers are allocated.
* When rows of data, partitioned with the same partition schema, pass from a partitioned step to another partitioned step, data is not repartitioned.
* When rows of data, partitioned with a different partition schema, pass from a partitioned step to another partitioned step, data is repartitioned.


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