I have tested Rockset for competitive analysis.
Good parts:
It has a slick and nice-looking UI. Good documentation. Many data loading options (including S3).
SQL support is good (Calcite?). Types are inferred on data loading. But you have to choose one "timestamp" column.
Bad parts:
First data load attempts failed (after 24 hours, it showed something like "too many retries").
I've loaded around 500 million rows, and the storage limit ran out.
Query performance did not shine. Storage size was very large (it seems they create many indices automatically).
Considerations:
The technology is not open-source. It is rocksdb + secondary indices + object storage + SQL engine.
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