Tuning Database Using Workload from Query Store with the Database Engine Tuning Advisor
Applies to: 
SQL Server
The Query Store feature in SQL Server automatically captures a history of queries, plans, and runtime statistics, and persists this information in the database. The Database Engine Tuning Advisor (DTA) supports a new option to use the Query Store to automatically select an appropriate workload for tuning. For many users, this can take away the need to explicitly collect a workload for tuning.
This feature is only available if the database has the Query Store feature turned on. For more information, see Enabling the Query Store.
This feature is available with SQL Server Management Studio v16.4 or higher.
How To Tune a Workload from Query Store in Database Engine Tuning Advisor GUI
From the DTA GUI, select the radio button Query Store in the General pane to enable this feature (see figure below).
How To Tune a Workload from Query Store in dta.exe command line Utility
From the command line (dta.exe), choose the -iq option to select the workload from Query Store.
There are two additional options available via the command line that helps tune the behavior of DTA when selecting the workload from Query Store. These options not available via the GUI:
Number of workload events to tune: This option, specified using -n command line argument, allows the user to control how many events from the Query Store are tuned. By default, DTA uses a value of 1000 for this option. DTA always chooses the most expensive events by total duration.
Time windows of events to tune: Since the Query Store may contain queries that have executed a long time ago, this option allows the user to specify a past time window (in hours) when a query must have executed for it to be considered by DTA for tuning. This option is specified using -I command line argument.
See dta Utility for more information.
Difference between using workload from Query Store and Plan Cache
The difference between the Query Store and Plan Cache options is that the former contains a longer history of queries that have executed against the database, persisted across server restarts. On the other hand, the Plan Cache only contains a subset of recently executed queries whose plans are cached in memory. When the server restarts, the entries in the Plan Cache are discarded.