Turn on Query Store before the next incident

If Query Store is off, you lose the best flight recorder SQL Server has for plan regressions.

ALTER DATABASE [YourDatabase]
SET QUERY_STORE = ON (
    OPERATION_MODE = READ_WRITE,
    MAX_STORAGE_SIZE_MB = 1000,
    QUERY_CAPTURE_MODE = AUTO
);

Then verify:

SELECT actual_state_desc, readonly_reason, current_storage_size_mb, max_storage_size_mb
FROM sys.database_query_store_options;

Tips:

• Size storage for workload (1 GB is only a starting point)
• Do not leave it in read-only because the store filled up — alert on that
• Use it to compare plans before/after releases and stats changes
• Pair with wait stats for a complete story

Enabling Query Store is one of the highest-ROI “do it this week” tasks for production databases.