docs/en/operations/settings/overview.md
:::note XML-based Settings Profiles and configuration files are currently not supported for ClickHouse Cloud. To specify settings for your ClickHouse Cloud service, you must use SQL-driven Settings Profiles. :::
There are following main groups of ClickHouse settings:
Global settings apply by default unless overridden at further levels. Session settings can be specified via profiles, user configuration and SET commands. Query settings can be provided via SETTINGS clause and are applied to individual queries. Background operations settings are applied to Mutations, Merges and potentially other operations, executed asynchronously in the background.
To view which settings have been changed from their default value you can query the
system.settings table:
SELECT name, value FROM system.settings WHERE changed
If no settings have been changed from their default value, then ClickHouse will return nothing.
To check the value of a particular setting, you can specify the name of the
setting in your query:
SELECT name, value FROM system.settings WHERE name = 'max_threads'
Which will return something like this:
┌─name────────┬─value─────┐
│ max_threads │ 'auto(8)' │
└─────────────┴───────────┘
1 row in set. Elapsed: 0.002 sec.