Server packets
| value | name | description |
|---|---|---|
| 0 | Hello | Server handshake response |
| 1 | Data | Same as client data |
| 2 | Exception | Query processing exception |
| 3 | Progress | Query progress |
| 4 | Pong | Ping response |
| 5 | EndOfStream | All packets were transferred |
| 6 | ProfileInfo | Profiling data |
| 7 | Totals | Total values |
| 8 | Extremes | Extreme values (min, max) |
| 9 | TablesStatusResponse | Response to TableStatus request |
| 10 | Log | Query system log |
| 11 | TableColumns | Columns description |
| 12 | UUIDs | List of unique parts ids |
| 13 | ReadTaskRequest | String (UUID) describes a request for which next task is needed |
| 14 | ProfileEvents | Packet with profile events from server |
The Data, Totals and Extremes can be compressed.
Hello
Response to client hello.
| field | type | value | description |
|---|---|---|---|
| name | String | Clickhouse | Server name |
| version_major | UVarInt | 21 | Server major version |
| version_minor | UVarInt | 12 | Server minor version |
| revision | UVarInt | 54452 | Server revision |
| tz | String | Europe/Moscow | Server timezone |
| display_name | String | Clickhouse | Server name for UI |
| version_patch | UVarInt | 3 | Server patch version |
Exception
Server exception during query processing.
| field | type | value | description |
|---|---|---|---|
| code | Int32 | 60 | See ErrorCodes.cpp. |
| name | String | DB::Exception | Server major version |
| message | String | DB::Exception: Table X doesn't exist | Server minor version |
| stack_trace | String | ~ | C++ stack trace |
| nested | Bool | true | More errors |
Can be continuous list of exceptions until nested is false.
Progress
Progress of query execution periodically reported by server.
Tip
Progress reported in deltas. For totals, accumulate it on client.
| field | type | value | description |
|---|---|---|---|
| rows | UVarInt | 65535 | Row count |
| bytes | UVarInt | 871799 | Byte count |
| total_rows | UVarInt | 0 | Total rows |
| wrote_rows | UVarInt | 0 | Rows from client |
| wrote_bytes | UVarInt | 0 | Bytes from client |
Pong
Response for client ping, no packet body.
End of stream
No more Data packets will be sent, query result is fully steamed from server to client.
No packet body.
Profile info
| field | type |
|---|---|
| rows | UVarInt |
| blocks | UVarInt |
| bytes | UVarInt |
| applied_limit | Bool |
| rows_before_limit | UVarInt |
| calculated_rows_before_limit | Bool |
Log
Data block with server log.
Tip
Encoded as data block of columns, but is never compressed.
| column | type |
|---|---|
| time | DateTime |
| time_micro | UInt32 |
| host_name | String |
| query_id | String |
| thread_id | UInt64 |
| priority | Int8 |
| source | String |
| text | String |
Profile events
Data block with profile events.
Tip
Encoded as data block of columns, but is never compressed.
The value type is UInt64 or Int64, depending on server revision.
| column | type |
|---|---|
| host_name | String |
| current_time | DateTime |
| thread_id | UInt64 |
| type | Int8 |
| name | String |
| value | UInt64 or Int64 |