How do you query Big Objects using SOQL vs Async SOQL, and why must you query indexed fields in exact order?

Standard SOQL on a Big Object (MyData__b) works but only on its index fields, and filters must follow the index order: you can filter on the first field, then first+second, etc. (equals on earlier fields, range allowed only on the last used field). Skipping an index field is not allowed. It supports limited operators and no ORDER BY outside index order.

Async SOQL was designed for large, long-running aggregate queries over Big Objects, writing results to a target object. It has been retired in recent releases, so confirm current alternatives (e.g. Bulk API 2.0 query jobs, Batch Apex, Data Cloud).

SELECT Account__c, Date__c FROM Order_History__b WHERE Account__c = '001...' AND Date__c > 2024-01-01T00:00:00Z