Contains information about threads that execute queries, for example, thread name, thread start time, duration of query processing.
To start logging:
ClickHouse does not delete data from the table automatically. See Introduction for more details.
You can use the log_queries_probability setting to reduce the number of queries, registered in the
event_date(Date) — The date when the thread has finished execution of the query.
event_time(DateTime) — The date and time when the thread has finished execution of the query.
event_time_microsecinds(DateTime) — The date and time when the thread has finished execution of the query with microseconds precision.
query_start_time(DateTime) — Start time of query execution.
query_start_time_microseconds(DateTime64) — Start time of query execution with microsecond precision.
query_duration_ms(UInt64) — Duration of query execution.
read_rows(UInt64) — Number of read rows.
read_bytes(UInt64) — Number of read bytes.
written_rows(UInt64) — For
INSERTqueries, the number of written rows. For other queries, the column value is 0.
written_bytes(UInt64) — For
INSERTqueries, the number of written bytes. For other queries, the column value is 0.
memory_usage(Int64) — The difference between the amount of allocated and freed memory in context of this thread.
peak_memory_usage(Int64) — The maximum difference between the amount of allocated and freed memory in context of this thread.
thread_name(String) — Name of the thread.
thread_number(UInt32) — Internal thread ID.
thread_id(Int32) — thread ID.
master_thread_id(UInt64) — OS initial ID of initial thread.
query(String) — Query string.
is_initial_query(UInt8) — Query type. Possible values:
- 1 — Query was initiated by the client.
- 0 — Query was initiated by another query for distributed query execution.
user(String) — Name of the user who initiated the current query.
query_id(String) — ID of the query.
address(IPv6) — IP address that was used to make the query.
port(UInt16) — The client port that was used to make the query.
initial_user(String) — Name of the user who ran the initial query (for distributed query execution).
initial_query_id(String) — ID of the initial query (for distributed query execution).
initial_address(IPv6) — IP address that the parent query was launched from.
initial_port(UInt16) — The client port that was used to make the parent query.
interface(UInt8) — Interface that the query was initiated from. Possible values:
- 1 — TCP.
- 2 — HTTP.
os_user(String) — OS’s username who runs clickhouse-client.
client_hostname(String) — Hostname of the client machine where the clickhouse-client or another TCP client is run.
client_name(String) — The clickhouse-client or another TCP client name.
client_revision(UInt32) — Revision of the clickhouse-client or another TCP client.
client_version_major(UInt32) — Major version of the clickhouse-client or another TCP client.
client_version_minor(UInt32) — Minor version of the clickhouse-client or another TCP client.
client_version_patch(UInt32) — Patch component of the clickhouse-client or another TCP client version.
http_method(UInt8) — HTTP method that initiated the query. Possible values:
- 0 — The query was launched from the TCP interface.
- 1 —
GETmethod was used.
- 2 —
POSTmethod was used.
http_user_agent(String) — The
UserAgentheader passed in the HTTP request.
quota_key(String) — The “quota key” specified in the quotas setting (see
revision(UInt32) — ClickHouse revision.
ProfileEvents(Map(String, UInt64)) — ProfileEvents that measure different metrics for this thread. The description of them could be found in the table system.events.
SELECT * FROM system.query_thread_log LIMIT 1 \G
event_time: 2020-09-11 10:08:17
event_time_microseconds: 2020-09-11 10:08:17.134042
query_start_time: 2020-09-11 10:08:17
query_start_time_microseconds: 2020-09-11 10:08:17.063150
query: INSERT INTO test1 VALUES
- system.query_log — Description of the
query_logsystem table which contains common information about queries execution.
- system.query_views_log — This table contains information about each view executed during a query.