system.settings

描述

包含当前用户会话参数设置信息。

列

name (String) — 设置名称。
value (String) — 设置值。
changed (UInt8) — 显示该设置是否已在配置中显式定义，或被显式修改。
description (String) — 设置的简短说明。
min (Nullable(String)) — 设置的最小值 (如果已通过约束设置) 。如果该设置没有最小值，则包含 NULL。
max (Nullable(String)) — 设置的最大值 (如果已通过约束设置) 。如果该设置没有最大值，则包含 NULL。
disallowed_values (Array(String)) — 不允许的值列表
readonly (UInt8) — 显示当前用户是否可以修改该设置：0 — 当前用户可以修改该设置，1 — 当前用户无法修改该设置。
type (String) — 可分配给该设置的值类型。
default (String) — 设置的默认值。
alias_for (String) — 如果该设置是另一个设置的别名，则为原始设置的名称。
is_obsolete (UInt8) — 显示该设置是否已过时。
tier (Enum8('Production' = 0, 'Obsolete' = 4, 'Experimental' = 8, 'Beta' = 12)) — 此功能的支持级别。ClickHouse 功能按等级划分，具体取决于其当前的开发状态以及使用时可预期的表现：

PRODUCTION：该功能稳定、安全可用，并且与其他 PRODUCTION 功能交互时不会出现问题。
BETA：该功能稳定且安全。与其他功能一起使用时的结果尚不明确，且不保证正确性。欢迎测试并反馈。
EXPERIMENTAL：该功能仍在开发中。仅适用于开发者和 ClickHouse 爱好者。该功能可能可用，也可能不可用，并且可能随时被移除。
OBSOLETE：不再受支持。它要么已被移除，要么将在未来版本中被移除。

示例

下面的示例展示如何获取名称包含 min_i 的设置的信息。

SELECT *
FROM system.settings
WHERE name LIKE '%min_insert_block_size_%'
FORMAT Vertical

Row 1:
──────
name:        min_insert_block_size_rows
value:       1048449
changed:     0
description: Sets the minimum number of rows in the block that can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones.

Possible values:

- Positive integer.
- 0 — Squashing disabled.
min:         ᴺᵁᴸᴸ
max:         ᴺᵁᴸᴸ
readonly:    0
type:        UInt64
default:     1048449
alias_for:   
is_obsolete: 0
tier:        Production

Row 2:
──────
name:        min_insert_block_size_bytes
value:       268402944
changed:     0
description: Sets the minimum number of bytes in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones.

Possible values:

- Positive integer.
- 0 — Squashing disabled.
min:         ᴺᵁᴸᴸ
max:         ᴺᵁᴸᴸ
readonly:    0
type:        UInt64
default:     268402944
alias_for:   
is_obsolete: 0
tier:        Production

Row 3:
──────
name:        min_insert_block_size_rows_for_materialized_views
value:       0
changed:     0
description: Sets the minimum number of rows in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones. This setting is applied only for blocks inserted into [materialized view](../../sql-reference/statements/create/view.md). By adjusting this setting, you control blocks squashing while pushing to materialized view and avoid excessive memory usage.

Possible values:

- Any positive integer.
- 0 — Squashing disabled.

## See Also            

- [min_insert_block_size_rows](/operations/settings/settings#min_insert_block_size_rows)
min:         ᴺᵁᴸᴸ
max:         ᴺᵁᴸᴸ
readonly:    0
type:        UInt64
default:     0
alias_for:   
is_obsolete: 0
tier:        Production

Row 4:
──────
name:        min_insert_block_size_bytes_for_materialized_views
value:       0
changed:     0
description: Sets the minimum number of bytes in the block which can be inserted into a table by an `INSERT` query. Smaller-sized blocks are squashed into bigger ones. This setting is applied only for blocks inserted into [materialized view](../../sql-reference/statements/create/view.md). By adjusting this setting, you control blocks squashing while pushing to materialized view and avoid excessive memory usage.

Possible values:

- Any positive integer.
- 0 — Squashing disabled.

## See Also            

- [min_insert_block_size_bytes](/operations/settings/settings#min_insert_block_size_bytes)
min:         ᴺᵁᴸᴸ
max:         ᴺᵁᴸᴸ
readonly:    0
type:        UInt64
default:     0
alias_for:   
is_obsolete: 0
tier:        Production

例如，需要检查以下内容时，使用 WHERE changed 很有用：

设置文件中的设置是否已正确加载并生效。
当前会话中已更改的设置。

SELECT * FROM system.settings WHERE changed AND name='load_balancing'

描述​

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示例​

另请参阅​

描述

列

示例

另请参阅