system.settings_changes

包含有关 ClickHouse 早期版本中设置变更信息的系统表。

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说明

包含有关 ClickHouse 早期版本中设置变更的信息。

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列

• type (Enum8(‘Session’ = 0, ‘MergeTree’ = 1)) — 设置所属的分组 (Session、MergeTree…)
• version (String) — ClickHouse 服务器版本。
• changes (Array(Tuple(name String, previous_value String, new_value String, reason String, compatibility_mode String))) — 设置变更。compatibility_mode：Apply 允许回滚到 previous_value；Ignore 会阻止回滚此项变更以及同一设置的更早变更。

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示例

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.')]

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另请参见

• 设置
• system.settings