April 7, 2026
When the Database Started Batching, the Queue Lost an Argument
ClickHouse 26.3 LTS batches small inserts inside the server, and two identical-looking OKs can now mean disk or memory
ClickHouse 26.3 LTS turns asynchronous inserts on by default: the change merged on 4 March and shipped in the LTS tag on 27 March. Write batching moved from the client into the server. The harder consequence is that what a returned OK is entitled to promise is now a setting, adjustable per query, and the response does not say which way it was set.
Ihor K
CEO