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4.7 KiB
4.7 KiB
system.settings
Contains information about session settings for current user.
Columns:
name(String) — Setting name.value(String) — Setting value.changed(UInt8) — Shows whether a setting is changed from its default value.description(String) — Short setting description.min(Nullable(String)) — Minimum value of the setting, if any is set via constraints. If the setting has no minimum value, contains NULL.max(Nullable(String)) — Maximum value of the setting, if any is set via constraints. If the setting has no maximum value, contains NULL.readonly(UInt8) — Shows whether the current user can change the setting:0— Current user can change the setting.1— Current user can’t change the setting.
Example
The following example shows how to get information about settings which name contains min_i.
SELECT *
FROM system.settings
WHERE name LIKE '%min_i%'
┌─name────────────────────────────────────────┬─value─────┬─changed─┬─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─min──┬─max──┬─readonly─┐
│ min_insert_block_size_rows │ 1048576 │ 0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
│ min_insert_block_size_bytes │ 268435456 │ 0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 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. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 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.
SELECT * FROM system.settings WHERE changed AND name='load_balancing'
See also