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[GitHub] [druid] petermarshallio opened a new pull request #11506: Docs - note when partitioning using concatenated dimensions

petermarshallio opened a new pull request #11506:
URL: https://github.com/apache/druid/pull/11506


   OTBO community Slack https://the-asf.slack.com/archives/CJ8D1JTB8/p1595434977062400
   - Note of caution when doing `single_dim` with concatenated dimensions.
   - Links to subheadings for each partitioning type
   - Slight wording changes
   
   This PR has:
   - [x] been self-reviewed.
   - [ ] been tested in a test Druid cluster.
   
   @techdocsmith


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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r680269754



##########
File path: docs/ingestion/native-batch.md
##########
@@ -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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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r688035224



##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  While it is possible to concatenate values from multiple
+> dimensions into a single new dimension that you then opt to specify in `partitionDimension`, remember that you
+> must use that new `partitionDimension` dimension in your
+> [native filter](https://druid.apache.org/docs/latest/querying/filters.html) /

Review comment:
       ```suggestion
   > [native filter](../querying/filters.md) /
   ```
   Use the relative path to the `.md` for links

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  While it is possible to concatenate values from multiple

Review comment:
       ```suggestion
   > the `partitionDimension` at query time.  You can concatenate values from multiple
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  While it is possible to concatenate values from multiple
+> dimensions into a single new dimension that you then opt to specify in `partitionDimension`, remember that you

Review comment:
       ```suggestion
   > dimensions into a new dimension to use as the `partitionDimension`. In this case, you
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  While it is possible to concatenate values from multiple
+> dimensions into a single new dimension that you then opt to specify in `partitionDimension`, remember that you
+> must use that new `partitionDimension` dimension in your
+> [native filter](https://druid.apache.org/docs/latest/querying/filters.html) /
+> [WHERE clause](https://druid.apache.org/docs/latest/querying/sql.html#where).

Review comment:
       ```suggestion
   > [WHERE clause](../querying/sql.md#where).
   ```
   Is this link necessary?




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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r698651218



##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+When you use this technique to partition your data, segment sizes may be unequally distributed if the data
+in your `partitionDimension` is also unequally distributed.  Therefore, to avoid imbalance in data layout, 
+ review the distribution of values in your source data before deciding on a partitioning strategy.
+
+For segment pruning to be effective and translate into better query performance, you must use
+the `partitionDimension` at query time.  You can concatenate values from multiple
+dimensions into a new dimension to use as the `partitionDimension`. In this case, you
+must use that new dimension in your native filter `WHERE` clause.
+> [native filter](../querying/filters.md) /

Review comment:
       ```suggestion
   ```




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[GitHub] [druid] petermarshallio commented on pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
petermarshallio commented on pull request #11506:
URL: https://github.com/apache/druid/pull/11506#issuecomment-895963406


   @techdocsmith I have merged our proposals – switched up the grammar and added some links, too.


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[GitHub] [druid] petermarshallio closed pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
petermarshallio closed pull request #11506:
URL: https://github.com/apache/druid/pull/11506


   


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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r698651218



##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+When you use this technique to partition your data, segment sizes may be unequally distributed if the data
+in your `partitionDimension` is also unequally distributed.  Therefore, to avoid imbalance in data layout, 
+ review the distribution of values in your source data before deciding on a partitioning strategy.
+
+For segment pruning to be effective and translate into better query performance, you must use
+the `partitionDimension` at query time.  You can concatenate values from multiple
+dimensions into a new dimension to use as the `partitionDimension`. In this case, you
+must use that new dimension in your native filter `WHERE` clause.
+> [native filter](../querying/filters.md) /

Review comment:
       ```suggestion
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+When you use this technique to partition your data, segment sizes may be unequally distributed if the data
+in your `partitionDimension` is also unequally distributed.  Therefore, to avoid imbalance in data layout, 
+ review the distribution of values in your source data before deciding on a partitioning strategy.
+
+For segment pruning to be effective and translate into better query performance, you must use
+the `partitionDimension` at query time.  You can concatenate values from multiple
+dimensions into a new dimension to use as the `partitionDimension`. In this case, you
+must use that new dimension in your native filter `WHERE` clause.
+> [native filter](../querying/filters.md) /
+> [WHERE clause](../querying/sql.md#where).

Review comment:
       ```suggestion
   ```




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[GitHub] [druid] techdocsmith merged pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith merged pull request #11506:
URL: https://github.com/apache/druid/pull/11506


   


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[GitHub] [druid] petermarshallio closed pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
petermarshallio closed pull request #11506:
URL: https://github.com/apache/druid/pull/11506


   


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[GitHub] [druid] techdocsmith merged pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith merged pull request #11506:
URL: https://github.com/apache/druid/pull/11506


   


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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r698651402



##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+When you use this technique to partition your data, segment sizes may be unequally distributed if the data
+in your `partitionDimension` is also unequally distributed.  Therefore, to avoid imbalance in data layout, 
+ review the distribution of values in your source data before deciding on a partitioning strategy.
+
+For segment pruning to be effective and translate into better query performance, you must use
+the `partitionDimension` at query time.  You can concatenate values from multiple
+dimensions into a new dimension to use as the `partitionDimension`. In this case, you
+must use that new dimension in your native filter `WHERE` clause.
+> [native filter](../querying/filters.md) /
+> [WHERE clause](../querying/sql.md#where).

Review comment:
       ```suggestion
   ```




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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r680269609



##########
File path: docs/ingestion/native-batch.md
##########
@@ -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.

Review comment:
       ```suggestion
   If you use this technique to partition your data, you can wind up with varying segment sizes if the values for `partitionDimension` from your original data are unequally distributed.
   ```
   @petermarshallio , is there a recommended action in this case? Select another dimension? Can autocompaction help?

##########
File path: docs/ingestion/native-batch.md
##########
@@ -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

Review comment:
       ```suggestion
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -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, you must use the newly concatenated dimension at query time.
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -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

Review comment:
       ```suggestion
   ```




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[GitHub] [druid] techdocsmith commented on a change in pull request #11506: Docs - note when partitioning using concatenated dimensions

Posted by GitBox <gi...@apache.org>.
techdocsmith commented on a change in pull request #11506:
URL: https://github.com/apache/druid/pull/11506#discussion_r694382528



##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and

Review comment:
       ```suggestion
   in your `partitionDimension` is also unequally distributed.  Therefore, to avoid imbalance in data layout, 
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  You can concatenate values from multiple

Review comment:
       ```suggestion
   the `partitionDimension` at query time.  You can concatenate values from multiple
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  You can concatenate values from multiple
+> dimensions into a new dimension to use as the `partitionDimension`. In this case, you

Review comment:
       ```suggestion
   dimensions into a new dimension to use as the `partitionDimension`. In this case, you
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use
+> the `partitionDimension` at query time.  You can concatenate values from multiple
+> dimensions into a new dimension to use as the `partitionDimension`. In this case, you
+> must use that new `partitionDimension` dimension in your

Review comment:
       ```suggestion
   must use that new dimension in your native filter `WHERE` clause.
   ```
   I'm not convinced links are doing much work here. (maybe to filters).

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.

Review comment:
       ```suggestion
    review the distribution of values in your source data before deciding on a partitioning strategy.
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data

Review comment:
       ```suggestion
   When you use this technique to partition your data, segment sizes may be unequally distributed if the data
   ```

##########
File path: docs/ingestion/native-batch.md
##########
@@ -369,11 +369,16 @@ Druid currently supports only one partition function.
 
 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.
+> When using this technique to partition your data, segment sizes may be unequally distributed if the data
+> in your `partitionDimension` is also unequally distributed.  Therefore, avoid imbalance in data layout and
+> review the distribution of values in your source data before deciding on a partitioning strategy.
+
+> In order for segment pruning to be effective and translate into better query performance, you _must_ use

Review comment:
       ```suggestion
   For segment pruning to be effective and translate into better query performance, you must use
   ```
   we don't use ital for emphasis. "must" is enough emphasis




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