If lookups are not sufficient, you can entirely rebuild Druid segments for specific intervals of time.
Rebuilding a segment is known as reindexing the data.
There are 3 scenarios in which you might want to update a data source's fields or connections: Refreshing, reconnecting, or resetting a data source can cause significant changes to the data source and any reports that use it. Otherwise, your reports may not show the correct data.
For example, if you want to add or remove columns from your existing segments, or you want to change the rollup granularity of your segments, you will have to reindex your data.
We recommend keeping a copy of your raw data around in case you ever need to reindex your data.
Any fields that have changed in name or data type will provide errors in the Data pane, seen as red exclamation marks.
By right-clicking on the field with the error, an option to replace the field references helps you to update the field from the original data connection with the appropriate field from the new connection.