ClickHouse/docs/en/operations/system-tables/settings.md
Robert Schulze 978a0c9cab
+ test
2023-09-26 10:45:50 +00:00

60 lines
5.9 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
slug: /en/operations/system-tables/settings
---
# settings
Contains information about session settings for current user.
Columns:
- `name` ([String](../../sql-reference/data-types/string.md)) — Setting name.
- `value` ([String](../../sql-reference/data-types/string.md)) — Setting value.
- `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether a setting is changed from its default value.
- `description` ([String](../../sql-reference/data-types/string.md)) — Short setting description.
- `min` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Minimum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no minimum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
- `max` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Maximum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no maximum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
- `readonly` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether the current user can change the setting:
- `0` — Current user can change the setting.
- `1` — Current user cant change the setting.
- `default` ([String](../../sql-reference/data-types/string.md)) — Setting default value.
- `is_obsolete` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) - Shows whether a setting is obsolete.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 settings which name contains `min_i`.
``` sql
SELECT *
FROM system.settings
WHERE name LIKE '%min_i%'
```
``` text
┌─name───────────────────────────────────────────────_─value─────_─changed─_─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────_─min──_─max──_─readonly─_─type─────────_─default───_─alias_for─_─is_obsolete─┐
│ min_insert_block_size_rows │ 1048449 │ 0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough. │ ____ │ ____ │ 0 │ UInt64 │ 1048449 │ │ 0 │
│ min_insert_block_size_bytes │ 268402944 │ 0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough. │ ____ │ ____ │ 0 │ UInt64 │ 268402944 │ │ 0 │
│ min_insert_block_size_rows_for_materialized_views │ 0 │ 0 │ Like min_insert_block_size_rows, but applied only during pushing to MATERIALIZED VIEW (default: min_insert_block_size_rows) │ ____ │ ____ │ 0 │ UInt64 │ 0 │ │ 0 │
│ min_insert_block_size_bytes_for_materialized_views │ 0 │ 0 │ Like min_insert_block_size_bytes, but applied only during pushing to MATERIALIZED VIEW (default: min_insert_block_size_bytes) │ ____ │ ____ │ 0 │ UInt64 │ 0 │ │ 0 │
│ read_backoff_min_interval_between_events_ms │ 1000 │ 0 │ Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time. │ ____ │ ____ │ 0 │ Milliseconds │ 1000 │ │ 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.
- Settings that changed in the current session.
<!-- -->
``` sql
SELECT * FROM system.settings WHERE changed AND name='load_balancing'
```
**See also**
- [Settings](../../operations/settings/index.md#session-settings-intro)
- [Permissions for Queries](../../operations/settings/permissions-for-queries.md#settings_readonly)
- [Constraints on Settings](../../operations/settings/constraints-on-settings.md)
- [SHOW SETTINGS](../../sql-reference/statements/show.md#show-settings) statement