(Timescale DevRel here)

We've recently been working through a detailed benchmark of TimescaleDB and Clickhouse. The DELETE/UPDATE question has been an intriguing story to follow - and I honestly hadn't considered the GDPR angle.

ATM, Clickhouse is still OLAP focused and their MergeTree implementation does not allow direct DELETE (or UPDATE) of any data. All DELETE/UPDATE requests are applied asynchronously by (essentially) re-writing/merging the table data (it's referred to as a "mutation") without whatever data was referenced in the DELETE/UPDATE. [1]

[1]: https://clickhouse.com/docs/en/sql-reference/statements/alte...