mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-21 01:00:48 +00:00
49 lines
2.5 KiB
Markdown
49 lines
2.5 KiB
Markdown
|
# system.trace_log {#system_tables-trace_log}
|
||
|
|
|
||
|
|
Contains stack traces collected by the sampling query profiler.
|
||
|
|
|
||
|
|
ClickHouse creates this table when the [trace\_log](../server-configuration-parameters/settings.md#server_configuration_parameters-trace_log) server configuration section is set. Also the [query_profiler_real_time_period_ns](../settings/settings.md#query_profiler_real_time_period_ns) and [query_profiler_cpu_time_period_ns](../settings/settings.md#query_profiler_cpu_time_period_ns) settings should be set.
|
||
|
|
|
||
|
|
To analyze logs, use the `addressToLine`, `addressToSymbol` and `demangle` introspection functions.
|
||
|
|
|
||
|
|
Columns:
|
||
|
|
|
||
|
|
- `event_date`([Date](../../sql-reference/data-types/date.md)) — Date of sampling moment.
|
||
|
|
|
||
|
|
- `event_time`([DateTime](../../sql-reference/data-types/datetime.md)) — Timestamp of sampling moment.
|
||
|
|
|
||
|
|
- `revision`([UInt32](../../sql-reference/data-types/int-uint.md)) — ClickHouse server build revision.
|
||
|
|
|
||
|
|
When connecting to server by `clickhouse-client`, you see the string similar to `Connected to ClickHouse server version 19.18.1 revision 54429.`. This field contains the `revision`, but not the `version` of a server.
|
||
|
|
|
||
|
|
- `timer_type`([Enum8](../../sql-reference/data-types/enum.md)) — Timer type:
|
||
|
|
|
||
|
|
- `Real` represents wall-clock time.
|
||
|
|
- `CPU` represents CPU time.
|
||
|
|
|
||
|
|
- `thread_number`([UInt32](../../sql-reference/data-types/int-uint.md)) — Thread identifier.
|
||
|
|
|
||
|
|
- `query_id`([String](../../sql-reference/data-types/string.md)) — Query identifier that can be used to get details about a query that was running from the [query_log](#system_tables-query_log) system table.
|
||
|
|
|
||
|
|
- `trace`([Array(UInt64)](../../sql-reference/data-types/array.md)) — Stack trace at the moment of sampling. Each element is a virtual memory address inside ClickHouse server process.
|
||
|
|
|
||
|
|
**Example**
|
||
|
|
|
||
|
|
``` sql
|
||
|
|
SELECT * FROM system.trace_log LIMIT 1 \G
|
||
|
|
```
|
||
|
|
|
||
|
|
``` text
|
||
|
|
Row 1:
|
||
|
|
──────
|
||
|
|
event_date: 2019-11-15
|
||
|
|
event_time: 2019-11-15 15:09:38
|
||
|
|
revision: 54428
|
||
|
|
timer_type: Real
|
||
|
|
thread_number: 48
|
||
|
|
query_id: acc4d61f-5bd1-4a3e-bc91-2180be37c915
|
||
|
|
trace: [94222141367858,94222152240175,94222152325351,94222152329944,94222152330796,94222151449980,94222144088167,94222151682763,94222144088167,94222151682763,94222144088167,94222144058283,94222144059248,94222091840750,94222091842302,94222091831228,94222189631488,140509950166747,140509942945935]
|
||
|
|
```
|
||
|
|
|
||
|
|
[Оригинальная статья](https://clickhouse.tech/docs/ru/operations/system_tables/trace_log) <!--hide-->
|