mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-16 04:32:33 +00:00
67 lines
7.3 KiB
Markdown
67 lines
7.3 KiB
Markdown
---
|
|
slug: /en/operations/system-tables/server_settings
|
|
---
|
|
# server_settings
|
|
|
|
Contains information about global settings for the server, which were specified in `config.xml`.
|
|
Currently, the table shows only settings from the first layer of `config.xml` and doesn't support nested configs (e.g. [logger](../../operations/server-configuration-parameters/settings.md#logger)).
|
|
|
|
Columns:
|
|
|
|
- `name` ([String](../../sql-reference/data-types/string.md)) — Server setting name.
|
|
- `value` ([String](../../sql-reference/data-types/string.md)) — Server setting value.
|
|
- `default` ([String](../../sql-reference/data-types/string.md)) — Server setting default value.
|
|
- `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether a setting was specified in `config.xml`
|
|
- `description` ([String](../../sql-reference/data-types/string.md)) — Short server setting description.
|
|
- `type` ([String](../../sql-reference/data-types/string.md)) — Server setting value type.
|
|
- `changeable_without_restart` ([Enum8](../../sql-reference/data-types/enum.md)) — Whether the setting can be changed at server runtime. Values:
|
|
- `'No' `
|
|
- `'IncreaseOnly'`
|
|
- `'DecreaseOnly'`
|
|
- `'Yes'`
|
|
- `is_obsolete` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) - Shows whether a setting is obsolete.
|
|
|
|
**Example**
|
|
|
|
The following example shows how to get information about server settings which name contains `thread_pool`.
|
|
|
|
``` sql
|
|
SELECT *
|
|
FROM system.server_settings
|
|
WHERE name LIKE '%thread_pool%'
|
|
```
|
|
|
|
``` text
|
|
┌─name──────────────────────────────────────────┬─value─┬─default─┬─changed─┬─description─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─type───┬─changeable_without_restart─┬─is_obsolete─┐
|
|
│ max_thread_pool_size │ 10000 │ 10000 │ 0 │ The maximum number of threads that could be allocated from the OS and used for query execution and background operations. │ UInt64 │ No │ 0 │
|
|
│ max_thread_pool_free_size │ 1000 │ 1000 │ 0 │ The maximum number of threads that will always stay in a global thread pool once allocated and remain idle in case of insufficient number of tasks. │ UInt64 │ No │ 0 │
|
|
│ thread_pool_queue_size │ 10000 │ 10000 │ 0 │ The maximum number of tasks that will be placed in a queue and wait for execution. │ UInt64 │ No │ 0 │
|
|
│ max_io_thread_pool_size │ 100 │ 100 │ 0 │ The maximum number of threads that would be used for IO operations │ UInt64 │ No │ 0 │
|
|
│ max_io_thread_pool_free_size │ 0 │ 0 │ 0 │ Max free size for IO thread pool. │ UInt64 │ No │ 0 │
|
|
│ io_thread_pool_queue_size │ 10000 │ 10000 │ 0 │ Queue size for IO thread pool. │ UInt64 │ No │ 0 │
|
|
│ max_active_parts_loading_thread_pool_size │ 64 │ 64 │ 0 │ The number of threads to load active set of data parts (Active ones) at startup. │ UInt64 │ No │ 0 │
|
|
│ max_outdated_parts_loading_thread_pool_size │ 32 │ 32 │ 0 │ The number of threads to load inactive set of data parts (Outdated ones) at startup. │ UInt64 │ No │ 0 │
|
|
│ max_unexpected_parts_loading_thread_pool_size │ 32 │ 32 │ 0 │ The number of threads to load inactive set of data parts (Unexpected ones) at startup. │ UInt64 │ No │ 0 │
|
|
│ max_parts_cleaning_thread_pool_size │ 128 │ 128 │ 0 │ The number of threads for concurrent removal of inactive data parts. │ UInt64 │ No │ 0 │
|
|
│ max_backups_io_thread_pool_size │ 1000 │ 1000 │ 0 │ The maximum number of threads that would be used for IO operations for BACKUP queries │ UInt64 │ No │ 0 │
|
|
│ max_backups_io_thread_pool_free_size │ 0 │ 0 │ 0 │ Max free size for backups IO thread pool. │ UInt64 │ No │ 0 │
|
|
│ backups_io_thread_pool_queue_size │ 0 │ 0 │ 0 │ Queue size for backups IO thread pool. │ UInt64 │ No │ 0 │
|
|
└───────────────────────────────────────────────┴───────┴─────────┴─────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴────────┴────────────────────────────┴─────────────┘
|
|
|
|
```
|
|
|
|
Using of `WHERE changed` can be useful, for example, when you want to check
|
|
whether settings in configuration files are loaded correctly and are in use.
|
|
|
|
<!-- -->
|
|
|
|
``` sql
|
|
SELECT * FROM system.server_settings WHERE changed AND name='max_thread_pool_size'
|
|
```
|
|
|
|
**See also**
|
|
|
|
- [Settings](../../operations/system-tables/settings.md)
|
|
- [Configuration Files](../../operations/configuration-files.md)
|
|
- [Server Settings](../../operations/server-configuration-parameters/settings.md)
|