system.settings_changes

Contains information about setting changes in previous ClickHouse versions.

Columns:

• type (Enum8('Session' = 0, 'MergeTree' = 1)) — The group of settings (Session, MergeTree...)
• version (String) — The ClickHouse server version.
• changes (Array(Tuple(name String, previous_value String, new_value String, reason String))) — The list of changes in settings which changed the behaviour of ClickHouse.

Example

SELECT *
FROM system.settings_changes
WHERE version = '23.5'
FORMAT Vertical

Row 1:
──────
type:    Core
version: 23.5
changes: [('input_format_parquet_preserve_order','1','0','Allow Parquet reader to reorder rows for better parallelism.'),('parallelize_output_from_storages','0','1','Allow parallelism when executing queries that read from file/url/s3/etc. This may reorder rows.'),('use_with_fill_by_sorting_prefix','0','1','Columns preceding WITH FILL columns in ORDER BY clause form sorting prefix. Rows with different values in sorting prefix are filled independently'),('output_format_parquet_compliant_nested_types','0','1','Change an internal field name in output Parquet file schema.')]

See also

• Settings
• system.settings