DB::Exception: Part XXXXX intersects previous part YYYYY. It is a bug or a result of manual intervention in the ZooKeeper data.

This article explains how to resolve the DB::Exception error related to intersecting parts in ClickHouse, often caused by a race condition or manual intervention in the ZooKeeper data.

Why it occurs

When this error occurs, a table shows as readonly and the error states intersecting parts.

You can see the error in the logs or by

SELECT *
FROM system.replicas
WHERE is_readonly = 1

The error message looks like:

Code: 49. DB::Exception: Part XXXXX intersects previous part YYYYY. It is a bug or a result of manual intervention in the ZooKeeper data. (LOGICAL_ERROR) (version 21.12.4.1 (official build))

Cause of the Error

This error can be caused by a race condition between mergeSelectingTask and queue reinitialization.

Solution

Execute the following queries on all replicas:

DETACH TABLE table_name;  -- Required for DROP REPLICA

SYSTEM DROP REPLICA 'replica_name' FROM ZKPATH '/table_path_in_zk/'; -- It will remove everything from /table_path_in_zk

ATTACH TABLE table_name;  -- Table will be in readonly mode, because there is no metadata in ZK

Then execute the following on all replicas:

SYSTEM RESTORE REPLICA table_name;  -- It will detach all partitions, re-create metadata in ZK (like it's new empty table), and then attach all partitions back

SYSTEM SYNC REPLICA table_name; -- Wait for replicas to synchronize parts. Also it's recommended to check `system.detached_parts` on all replicas after recovery is finished.

You should upgrade to the latest version of ClickHouse

Additional resources

Related PRs and GitHub issues:

• ClickHouse/ClickHouse#34096
• ClickHouse/ClickHouse#30651
• ClickHouse/ClickHouse#31060
• ClickHouse/ClickHouse#35863

Versions affected:

ClickHouse v 22.12 and prior