techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r680269754
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File path: docs/ingestion/native-batch.md
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@@ -366,8 +366,15 @@ Druid currently supports only one partition function.
#### Single-dimension range partitioning
> Single dimension range partitioning is currently not supported in the
> sequential mode of the Parallel task.
+
The Parallel task will use one subtask when you set `maxNumConcurrentSubTasks`
to 1.
+> Be aware that, with this technique, segment sizes could be skewed if your
chosen `partitionDimension` is also skewed in source data.
+
+> While it is technically possible to concatenate multiple dimensions into a
single new dimension
+> that you go on to specify in `partitionDimension`, remember that you _must_
then use this newly concatenated dimension at query time
+> in order for segment pruning to be effective.
Review comment:
```suggestion
> It is possible to concatenate multiple dimensions into a single new
dimension to use for the `partitionDimension`. To take advantage of the
performance improvements of segment pruning in this case, filter on the newly
concatenated dimension at query time.
```
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