legacy
High Concurrency clusters
High Concurrency clusters is legacy, replaced by Standard and Dedicated access modes (legacy since August 2022).
Serverless pools High Concurrency clusters Shared / Single user access modes Standard and Dedicated access modes
The legacy cluster mode tuned for many concurrent users, running each user's code in separate processes for fine-grained sharing, and the only mode that supported Hive metastore table access control.
- It was the only cluster mode that supported table access control, which is how a security feature ended up bundled with a performance setting.
- Alone among cluster modes, it did not terminate automatically by default - Standard and Single Node shut off after 120 minutes, High Concurrency just kept running.
- Without table ACLs it was indistinguishable from a Standard cluster, and Databricks eventually said so out loud, folding both into the No isolation shared access mode.
Limitations: Not available at all in workspaces assigned to a Unity Catalog metastore, and limited to SQL, Python and R - Scala is unsupported because user code runs in separate processes.
Open in REbricked →- Category
- Compute / BI
- Also known as
- High Concurrency cluster mode, HC clusters, High Concurrency with Table ACLs
- Verified
- 2026-08-20