.alter table policy partitioning command

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

Change's the table's partitioning policy. The partitioning policy defines if and how extents (data shards) should be partitioned for a specific table or a materialized view.

Permissions

You must have at least Database Admin permissions to run this command.

Syntax

.alter table TableName policy partitioning PolicyObject

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
TableName	string	✔️	The name of the table to alter.
PolicyObject	string	✔️	A serialized JSON policy object. See partitioning policy.

Examples

Set a policy with a hash partition key:

.alter table [table_name] policy partitioning ```
{
  "PartitionKeys": [
    {
      "ColumnName": "my_string_column",
      "Kind": "Hash",
      "Properties": {
        "Function": "XxHash64",
        "MaxPartitionCount": 128,
        "PartitionAssignmentMode": "Uniform"
      }
    }
  ]
}```

Set 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",
        "OverrideCreationTime": false
      }
    }
  ]
}```

Set a policy with two kinds of partition keys:

.alter table [table_name] policy partitioning ```
{
  "PartitionKeys": [
    {
      "ColumnName": "my_string_column",
      "Kind": "Hash",
      "Properties": {
        "Function": "XxHash64",
        "MaxPartitionCount": 128,
        "PartitionAssignmentMode": "Uniform"
      }
    },
    {
      "ColumnName": "my_datetime_column",
      "Kind": "UniformRange",
      "Properties": {
        "Reference": "1970-01-01T00:00:00",
        "RangeSize": "1.00:00:00",
        "OverrideCreationTime": false
      }
    }
  ]
}```