techdocsmith commented on a change in pull request #11677:
URL: https://github.com/apache/druid/pull/11677#discussion_r725175308
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File path: docs/ingestion/rollup.md
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@@ -30,6 +30,8 @@ At ingestion time, you control rollup with the `rollup`
setting in the [`granula
When you disable rollup, Druid loads each row as-is without doing any form of
pre-aggregation. This mode is similar to databases that do not support a rollup
feature. Set `rollup` to `false` if you want Druid to store each record as-is,
without any rollup summarization.
+Use roll-up to create a table datasource if you want best performance or are
working within a strict space constraint, and you don't need raw values from
[high-cardinality dimensions](schema-design.md#sketches). Conversely, disable
roll-up when you need a table that returns individual rows or when you need to
be able to execute `GROUP BY` or `WHERE` queries on _any_ column. If there are
multiple needs, multiple tables with different roll-up configurations are a
possible solution.
Review comment:
```suggestion
Use roll-up when creating a table datasource if both:
- You want optimal performance or you have strict space constraints.
- You don't need raw values from [high-cardinality
dimensions](schema-design.md#sketches).
Conversely, disable roll-up if either:
- You need results for individual rows.
- You need to execute `GROUP BY` or `WHERE` queries on _any_ column.
If you have conflicting needs for different use cases, you can create
multiple tables with different roll-up configurations on each table.
```
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