User goal: It should be possible for users to trigger server-side sorting from the Lens editor in at least some cases.

Technical background: The Lens architecture does not currently support this kind of sorting for several reasons, but primarily because of the separation between data sources and visualizations. Also, Elasticsearch doesn't support every kind of sorting, and this might need to be represented in our datasources.

As it exists today, the only sortable operation in Lens is the Terms aggregation, which can be sorted:

• In up or down order by referencing another metric in Lens, such as Count or Sum.
  • Sorting in ascending order is not recommended, but we currently allow it.
• Alphabetically up or down
• (Not implemented) Using the default sort order, count

For the data table visualization to know that these limitations exist, we would need these architectural changes, provided via the getOperation function on data sources.

• Operations need to indicate whether they are currently sorted, and if are capable of being sorted
• If they are capable of being sorted, datasources need to handle the sorting interaction
• References probably need to be provided to sort columns