General Errors
DB::Exception: Not enough space– Insufficient disk space.DB::Exception: Memory limit exceeded– Query exceeds memory limits.DB::Exception: Too many parts– Too many active data parts in a table, causing performance issues.DB::Exception: Table is in readonly mode– The table is in read-only mode due to metadata issues or storage settings.DB::Exception: Cannot load table– Table metadata is corrupted or missing.DB::Exception: Table structure does not match– Schema mismatch when attaching a table.DB::Exception: Not found column– Query references a non-existent column.DB::Exception: Directory already exists– Issue when creating or renaming tables with existing directories.
Syntax & Query Errors
Syntax error: failed at position X– Incorrect SQL syntax.DB::Exception: Aggregate function requires parameters– Missing or incorrect arguments for an aggregate function.DB::Exception: Unknown function– Using an undefined function.DB::Exception: Invalid number of arguments– Function called with an incorrect number of arguments.DB::Exception: Division by zero– Attempting to divide by zero.DB::Exception: Nested type mismatch– Type mismatch in nested structures likeArray(Tuple(...)).
Storage & Replication Errors
DB::Exception: Too many parts (merge is lagging)– Table has too many small parts, causing merge issues.DB::Exception: Replica is lost– Replicated table lost its metadata or connection to the cluster.DB::Exception: ZooKeeper node exists– Replication conflict with existing metadata.DB::Exception: Cannot create a new ZooKeeper session– ClickHouse cannot connect to ZooKeeper.DB::Exception: No active replicas– All replicas of a table are down or lagging.DB::Exception: Unknown status of replica– ClickHouse cannot determine the replica's state.
Authentication & Permission Errors
DB::Exception: Access denied– User lacks the necessary privileges.DB::Exception: User does not exist– Attempting to authenticate with a non-existent user.DB::Exception: Wrong password– Incorrect password provided for authentication.DB::Exception: Cannot write to table– Write operation denied due to permission restrictions.
Network & Connectivity Issues
DB::Exception: Connection refused– ClickHouse server is unreachable.DB::Exception: Read timeout– Query exceeded network timeout.DB::Exception: Cannot read from socket– Network failure while fetching data.DB::Exception: Too many simultaneous connections– Exceeded the maximum allowed client connections.
MergeTree & Engine-Specific Errors
DB::Exception: Cannot merge parts– Merge operation failure due to disk issues or corrupted data.DB::Exception: Merge is manually disabled– Merge operations disabled for the table.DB::Exception: Part is already merged into another part– Data inconsistency in a ReplicatedMergeTree table.DB::Exception: Part is not in expected state– MergeTree part is in an unexpected state.
Data Type & Format Errors
DB::Exception: Cannot parse JSON– JSON data format is invalid.DB::Exception: Cannot parse DateTime– Incorrect date/time format in an insert or query.DB::Exception: Type mismatch– Provided data type does not match the column type.DB::Exception: Cannot convert– Conversion between incompatible types.DB::Exception: Data too large for column– Inserted data exceeds the column’s defined size.
Distributed Queries & Sharding Errors
DB::Exception: There is no query for id– The distributed query ID is not found.DB::Exception: Shard is unavailable– One or more shards in a distributed table are down.DB::Exception: Distributed query execution failed– General failure in a distributed query.
