gargvishesh commented on code in PR #16681:
URL: https://github.com/apache/druid/pull/16681#discussion_r1794682705


##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.

Review Comment:
   ```suggestion
   where `longSum` being capable of combining partial results satisfies 
mergeability, while input and output column being the same (`added`) ensures 
idempotency.
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:

Review Comment:
   ```suggestion
   Auto-compaction using the MSQ task engine supports only aggregators that 
satisfy the following properties: 
   a) mergeability: can also be used to combine partial aggregates
   b) idempotency: produce the same results on repeated runs of the aggregator 
on previously aggregated values in a column
   
   This is exemplified by the following `longSum` aggregator:
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.

Review Comment:
   Segment sorting limitation is lifted now but holds true for commits in druid 
31
   ```suggestion
   - The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
   - Segments can only be sorted on `__time` as the first column.
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.
+
+The following are some examples of aggregators that aren't supported, where 
each run of the aggregator produces different results:
+
+*  `longSum` aggregator where the `added` column rolls up into the `sum_added` 
column:
+    ```
+    {"name": "sum_added", "type": "longSum", "fieldName": "added" }
+    ```
+* Partial sketches:

Review Comment:
   ```suggestion
   * Partial sketches which cannot themselves be used to combine partial 
aggregates and need merging aggregators -- such as `HLLSketchMerge` required 
for `HLLSketchBuild` aggregator below -- violating mergeability:
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,126 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine and [MSQ task 
engine](#use-msq-for-auto-compaction) are available
+* More reactive and submit tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       ...

Review Comment:
   Shall we also include the above on `Automatic compaction dynamic 
configuration` page?



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.
+
+The following are some examples of aggregators that aren't supported, where 
each run of the aggregator produces different results:
+
+*  `longSum` aggregator where the `added` column rolls up into the `sum_added` 
column:
+    ```
+    {"name": "sum_added", "type": "longSum", "fieldName": "added" }
+    ```
+* Partial sketches:
+    ```
+    {"name": added, "type":"HLLSketchMerge", fieldName: added}

Review Comment:
   ```suggestion
       {"name": added, "type":"HLLSketchBuild", fieldName: added}
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.
+
+The following are some examples of aggregators that aren't supported, where 
each run of the aggregator produces different results:
+
+*  `longSum` aggregator where the `added` column rolls up into the `sum_added` 
column:

Review Comment:
   ```suggestion
   *  `longSum` aggregator where the `added` column rolls up into `sum_added` 
column discarding the input `added` column, violating idempotency, as 
subsequent runs would no longer find the `added` column:
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.
+
+The following are some examples of aggregators that aren't supported, where 
each run of the aggregator produces different results:

Review Comment:
   ```suggestion
   The following are some examples of aggregators that aren't supported since 
at least of the required conditions aren't satisfied:
   ```



##########
docs/data-management/automatic-compaction.md:
##########
@@ -221,6 +223,128 @@ The following auto-compaction configuration compacts 
updates the `wikipedia` seg
 }
 ```
 
+## Auto-compaction using compaction supervisors  
+
+:::info Experimental
+Compaction supervisors are experimental. For production use, we recommend 
[Coordinator-based auto-compaction](#auto-compaction-using-coordinator-duties).
+:::
+
+You can run automatic compaction using compaction supervisors on the Overlord 
rather than Coordinator duties. Compaction supervisors provide the following 
benefits over Coordinator duties:
+
+* Can use the supervisor framework to get information about the 
auto-compaction, such as status or state
+* More easily suspend or resume compaction for a datasource
+* Can use either the native compaction engine or the [MSQ task 
engine](#use-msq-for-auto-compaction)
+* More reactive and submits tasks as soon as a compaction slot is available
+* Tracked compaction task status to avoid re-compacting an interval repeatedly
+
+
+To use compaction supervisors, set the following properties in your Overlord 
runtime properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  `druid.supervisor.compaction.engine` to  `msq` to specify the MSQ task 
engine as the compaction engine or to `native` to use the native engine.
+
+Compaction uses the same syntax as Coordinator-based auto-compaction with some 
differences. Specifically, you submit a supervisor spec with the `type` set to 
`autocompact` and the auto-compaction config in the `spec` to configure 
auto-compaction.
+  
+For information about the syntax, see [automatic-compaction 
syntax](#auto-compaction-syntax). 
+
+### Manage compaction supervisors with the web console
+
+To submit a supervisor spec for MSQ task engine automatic compaction, perform 
the following steps:
+
+1. In the web console, go to the **Supervisors** tab.
+1. Click **...** > **Submit JSON supervisor**.
+1. In the dialog, include the following:
+     - The type of supervisor spec by setting `"type": "autocompact"`
+     - The compaction configuration by adding it to the `spec` field
+    ```json
+    {
+   "type": "autocompact",
+   "spec": {
+      "dataSource": YOUR_DATASOURCE,
+    ...
+    ...
+   }
+    ```
+1. Submit the supervisor.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Manage compaction supervisors with supervisor APIs
+
+Submitting an automatic compaction as a supervisor task uses the same endpoint 
as supervisor tasks for streaming ingestion.
+
+The following example configures auto-compaction for the `wikipedia` 
datasource:
+
+```sh
+curl --location --request POST 
'http://localhost:8081/druid/indexer/v1/supervisor' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+   "type": "autocompact",    // required
+   "suspended": false,         // optional
+   "spec": {                           // required
+       "dataSource": "wikipedia",          // required
+       "tuningConfig": {...},                    // optional
+       "granularitySpec": {...},               // optional
+       "engine": <native|msq>,  //optional
+       ...
+   }
+}'
+```
+
+Note that if you omit `spec.engine`, Druid uses the default compaction engine. 
You can control the default compaction engine with the 
`druid.supervisor.compaction.engine` Overlord runtime property. If 
`spec.engine` and `druid.supervisor.compaction.engine` are omitted, Druid 
defaults to the native engine.
+
+To stop the automatic compaction task, suspend or terminate the supervisor 
through the UI or API.
+
+### Use MSQ for auto-compaction
+
+The MSQ task engine is available as a compaction engine if you configure 
auto-compaction to use compaction supervisors. To use the MSQ task engine for 
automatic compaction, make sure the following requirements are met:
+
+* Have the [MSQ  task engine extension 
loaded](../multi-stage-query/index.md#load-the-extension).
+* In your Overlord runtime properties, set the following properties:
+  *  `druid.supervisor.compaction.enabled` to `true` so that compaction tasks 
can be run as a supervisor task
+  *  Optionally, set `druid.supervisor.compaction.engine` to `msq` to specify 
the MSQ task engine as the default compaction engine. If you don't do this, 
you'll need to set `spec.engine` to `msq` for each compaction supervisor spec 
where you want to use the MSQ task engine.
+* Have at least two compaction task slots available or set 
`compactionConfig.taskContext.maxNumTasks` to two or more. The MSQ task engine 
requires at least two tasks to run, one controller task and one worker task.
+
+You can use [MSQ task engine context 
parameters](../multi-stage-query/reference.md#context-parameters) in 
`spec.taskContext` when configuring your datasource for automatic compaction, 
such as setting the maximum number of tasks using the 
`spec.taskContext.maxNumTasks` parameter. Some of the MSQ task engine context 
parameters overlap with automatic compaction parameters. When these settings 
overlap, set one or the other.
+To submit an automatic compaction task, you submit a supervisor spec through 
the UI or API with the type `autocompact` and the `spec` where you define the 
compaction behavior using the [automatic compaction 
syntax](#auto-compaction-syntax). You can also use the [web 
console](#manage-compaction-supervisors-with-the-web-console).
+
+
+#### MSQ task engine limitations
+
+When using the MSQ task engine for auto-compaction, keep the following 
limitations in mind:
+
+- The `metricSpec` field is only supported for certain aggregators. For more 
information, see [Supported aggregators](#supported-aggregators).
+- Only dynamic and range-based partitioning are supported
+- Set `rollup`  to `true` if and only if `metricSpec` is not empty or null.
+- You can only partition on string dimensions. However, multi-valued string 
dimensions are not supported.
+- The `maxTotalRows` config is not supported in `DynamicPartitionsSpec`. Use 
`maxRowsPerSegment` instead.
+
+##### Supported aggregators
+
+Auto-compaction using the MSQ task engine only supports aggregators. Only 
aggregators where repeated runs of the aggregator on a column produce the same 
results each time, such as the following `longSum` aggregator:
+
+```
+{"name": "added", "type": "longSum", "fieldName": "added"}
+```
+
+where the input and output column are both `added`.
+
+The following are some examples of aggregators that aren't supported, where 
each run of the aggregator produces different results:
+
+*  `longSum` aggregator where the `added` column rolls up into the `sum_added` 
column:
+    ```
+    {"name": "sum_added", "type": "longSum", "fieldName": "added" }
+    ```
+* Partial sketches:
+    ```
+    {"name": added, "type":"HLLSketchMerge", fieldName: added}
+    ```
+* Count aggregators since it rolls up into a different count column

Review Comment:
   ```suggestion
   * Count aggregator since it cannot be used to combine partial aggregates and 
it rolls up into a different `count` column discarding the input column(s), 
violating both mergeability and idempotency.
   ```



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