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# AWS::OpenSearchServerless::Index Parameters
<a name="aws-properties-opensearchserverless-index-parameters"></a>

Additional parameters for the k-NN algorithm.

## Syntax
<a name="aws-properties-opensearchserverless-index-parameters-syntax"></a>

To declare this entity in your CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-opensearchserverless-index-parameters-syntax.json"></a>

```
{
  "[EfConstruction](#cfn-opensearchserverless-index-parameters-efconstruction)" : Integer,
  "[M](#cfn-opensearchserverless-index-parameters-m)" : Integer
}
```

### YAML
<a name="aws-properties-opensearchserverless-index-parameters-syntax.yaml"></a>

```
  [EfConstruction](#cfn-opensearchserverless-index-parameters-efconstruction): Integer
  [M](#cfn-opensearchserverless-index-parameters-m): Integer
```

## Properties
<a name="aws-properties-opensearchserverless-index-parameters-properties"></a>

`EfConstruction`  <a name="cfn-opensearchserverless-index-parameters-efconstruction"></a>
The size of the dynamic list used during k-NN graph creation.  
*Required*: No  
*Type*: Integer  
*Minimum*: `1`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`M`  <a name="cfn-opensearchserverless-index-parameters-m"></a>
Number of neighbors to consider during k-NN search.  
*Required*: No  
*Type*: Integer  
*Minimum*: `2`  
*Maximum*: `100`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)