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7.4 KiB
7.4 KiB
slug | machine_translated | machine_translated_rev |
---|---|---|
/zh/operations/system-tables/dictionaries | true | 5decc73b5d |
系统。字典
包含以下信息 外部字典.
列:
database
(字符串) — Name of the database containing the dictionary created by DDL query. Empty string for other dictionaries.name
(字符串) — 字典名称.status
(枚举8) — Dictionary status. Possible values:NOT_LOADED
— Dictionary was not loaded because it was not used.LOADED
— Dictionary loaded successfully.FAILED
— Unable to load the dictionary as a result of an error.LOADING
— Dictionary is loading now.LOADED_AND_RELOADING
— Dictionary is loaded successfully, and is being reloaded right now (frequent reasons: SYSTEM RELOAD DICTIONARY 查询,超时,字典配置已更改)。FAILED_AND_RELOADING
— Could not load the dictionary as a result of an error and is loading now.
origin
(字符串) — Path to the configuration file that describes the dictionary.type
(字符串) — Type of dictionary allocation. 在内存中存储字典.key
— 密钥类型:数字键 (UInt64) or Сomposite key (字符串) — form “(type 1, type 2, ..., type n)”.attribute.names
(阵列(字符串)) — Array of 属性名称 由字典提供。attribute.types
(阵列(字符串)) — Corresponding array of 属性类型 这是由字典提供。bytes_allocated
(UInt64) — Amount of RAM allocated for the dictionary.query_count
(UInt64) — Number of queries since the dictionary was loaded or since the last successful reboot.hit_rate
(Float64) — For cache dictionaries, the percentage of uses for which the value was in the cache.element_count
(UInt64) — Number of items stored in the dictionary.load_factor
(Float64) — Percentage filled in the dictionary (for a hashed dictionary, the percentage filled in the hash table).source
(字符串) — Text describing the 数据源 为了字典lifetime_min
(UInt64) — Minimum 使用寿命 在内存中的字典,之后ClickHouse尝试重新加载字典(如果invalidate_query
被设置,那么只有当它已经改变)。 在几秒钟内设置。lifetime_max
(UInt64) — Maximum 使用寿命 在内存中的字典,之后ClickHouse尝试重新加载字典(如果invalidate_query
被设置,那么只有当它已经改变)。 在几秒钟内设置。loading_start_time
(日期时间) — Start time for loading the dictionary.last_successful_update_time
(日期时间) — End time for loading or updating the dictionary. Helps to monitor some troubles with external sources and investigate causes.loading_duration
(Float32) — Duration of a dictionary loading.last_exception
(字符串) — Text of the error that occurs when creating or reloading the dictionary if the dictionary couldn't be created.
示例
配置字典。
CREATE DICTIONARY dictdb.dict
(
`key` Int64 DEFAULT -1,
`value_default` String DEFAULT 'world',
`value_expression` String DEFAULT 'xxx' EXPRESSION 'toString(127 * 172)'
)
PRIMARY KEY key
SOURCE(CLICKHOUSE(HOST 'localhost' PORT 9000 USER 'default' TABLE 'dicttbl' DB 'dictdb'))
LIFETIME(MIN 0 MAX 1)
LAYOUT(FLAT())
确保字典已加载。
SELECT * FROM system.dictionaries
┌─database─┬─name─┬─status─┬─origin──────┬─type─┬─key────┬─attribute.names──────────────────────┬─attribute.types─────┬─bytes_allocated─┬─query_count─┬─hit_rate─┬─element_count─┬───────────load_factor─┬─source─────────────────────┬─lifetime_min─┬─lifetime_max─┬──loading_start_time─┌──last_successful_update_time─┬──────loading_duration─┬─last_exception─┐
│ dictdb │ dict │ LOADED │ dictdb.dict │ Flat │ UInt64 │ ['value_default','value_expression'] │ ['String','String'] │ 74032 │ 0 │ 1 │ 1 │ 0.0004887585532746823 │ ClickHouse: dictdb.dicttbl │ 0 │ 1 │ 2020-03-04 04:17:34 │ 2020-03-04 04:30:34 │ 0.002 │ │
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