分区策略命令partitioning policy command

• 08/18/2020
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此处详细介绍了数据分区策略。The data partitioning policy is detailed here.

显示策略show policy

.show table [table_name] policy partitioning

.show 命令显示应用于表的分区策略。The .show command displays the partitioning policy that is applied on the table.

输出Output

alter 和 alter-merge policyalter and alter-merge policy

.alter table [table_name] policy partitioning @'policy object, serialized as JSON'

.alter-merge table [table_name] policy partitioning @'partial policy object, serialized as JSON'

.alter 命令允许更改应用于表的分区策略。The .alter command allows changing the partitioning policy that is applied on the table.

此命令需要 DatabaseAdmin 权限。The command requires DatabaseAdmin permissions.

对策略的更改可能最多需要 1 小时才能生效。Changes to the policy could take up to 1 hour to take effect.

示例Examples

使用哈希分区键设置策略Setting a policy with a hash partition key

.alter table [table_name] policy partitioning @'{'
  '"PartitionKeys": ['
    '{'
      '"ColumnName": "my_string_column",'
      '"Kind": "Hash",'
      '"Properties": {'
        '"Function": "XxHash64",'
        '"MaxPartitionCount": 256,'
      '}'
    '}'
  ']'
'}'

使用统一范围日期/时间分区键设置策略Setting a policy with a uniform range datetime partition key

.alter table [table_name] policy partitioning @'{'
  '"PartitionKeys": ['
    '{'
      '"ColumnName": "my_datetime_column",'
      '"Kind": "UniformRange",'
      '"Properties": {'
        '"Reference": "1970-01-01T00:00:00",'
        '"RangeSize": "1.00:00:00"'
      '}'
    '}'
  ']'
'}'

使用两种分区键设置策略Setting a policy with both kinds of partition keys

.alter table [table_name] policy partitioning @'{'
  '"PartitionKeys": ['
    '{'
      '"ColumnName": "my_string_column",'
      '"Kind": "Hash",'
      '"Properties": {'
        '"Function": "XxHash64",'
        '"MaxPartitionCount": 256,'
      '}'
    '},'
    '{'
      '"ColumnName": "my_datetime_column",'
      '"Kind": "UniformRange",'
      '"Properties": {'
        '"Reference": "1970-01-01T00:00:00",'
        '"RangeSize": "1.00:00:00"'
      '}'
    '}'
  ']'
'}'

在表级别显式设置策略的特定属性Setting a specific property of the policy explicitly at table level

要将策略的 EffectiveDateTime 设置为其他值，请使用以下命令：To set the EffectiveDateTime of the policy to a different value, use the following command:

.alter-merge table [table_name] policy partitioning @'{"EffectiveDateTime":"2020-01-01"}'

删除策略delete policy

.delete table [table_name] policy partitioning

.delete 命令删除给定表的分区策略。The .delete command deletes the partitioning policy of the given table.