HTTP Response Headers
When a query is executed using the HTTP endpoint, the response contains informational headers.
HTTP/2 200
date: Tue, 29 Jun 2021 09:32:06 GMT
content-type: application/json; charset=UTF-8
x-clickhouse-query-id: c4f6aba2-480f-4f67-9d5d-5662e44b45dc
x-clickhouse-format: JSON
x-clickhouse-timezone: UTC
x-hdx-query-stats: exec_time=4271 rows_read=0 bytes_read=0 num_partitions=4 num_peers=2
| Header | Description | Example |
|---|---|---|
x-clickhouse-query-id | Unique query identifier | c4f6aba2-480f-4f67-9d5d-5662e44b45dc |
x-clickhouse-format | Format of the response body | JSON |
x-clickhouse-timezone | Time zone applied to the data | UTC |
x-hdx-query-stats | Query execution statistics, see detail | exec_time=545 rows_read=48516556 bytes_read=194066224 num_partitions=18 num_peers=1 |
x-hdx-query-stats
The Query stats supply the following information.
| Query_stat | Description |
|---|---|
exec_time | Execution time of the query in milliseconds |
catalog_resp_time_ms | Execution time of catalog query in milliseconds |
num_partitions | Number of HDX partitions accessed to answer the query |
memory_usage | Memory used in bytes |
head_rows_read | Count of rows handled by the query head |
head_bytes_read | Number of uncompressed bytes parsed to answer the query |
num_peers | Number of query peers accessed to answer the query |
query_attempts | Number of total times the query was tried, usually, 1 |
peer_rows_read | Count of rows read by all query peers |
peer_bytes_read | Number of uncompressed bytes parsed by query peers |
result_rows | Count of rows in the response set |
Updated 8 days ago