Time to live (TTL) duration for records - Amazon SageMaker AI
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Time to live (TTL) duration for records

Amazon SageMaker Feature Store provides the option for records to be hard deleted from the online store after a time duration is reached, with time to live (TTL) duration (TtlDuration). The record will expire after the record’s EventTime plus the TtlDuration is reached, or ExpiresAt = EventTime + TtlDuration. The TtlDuration can be applied at a feature group level, where all records within the feature group will have the TtlDuration by default, or at an individual record level. If TtlDuration is unspecified, the default value is null and the record will remain in the online store until it is overwritten.

A record deleted using TtlDuration is hard deleted, or completely removed from the online store, and the deleted record is added to the offline store. For more information on hard delete and deletion modes, see DeleteRecord in the Amazon SageMaker API Reference guide. When a record is hard deleted it immediately becomes inaccessible using Feature Store APIs.

Important

TTL typically deletes expired items within a few days. Depending on the size and activity level of a table, the actual delete operation of an expired item can vary. Because TTL is meant to be a background process, the nature of the capacity used to expire and delete items via TTL is variable (but free of charge). For more information on how items are deleted from a DynamoDB table, see How it works: DynamoDB Time to Live (TTL).

TtlDuration must be a dictionary containing a Unit and a Value, where the Unit must be a string with values "Seconds", "Minutes", "Hours", "Days", or "Weeks" and Value must be an integer greater than or equal to 1. TtlDuration can be applied while using the CreateFeatureGroup, UpdateFeatureGroup, and PutRecord APIs. See the request and response syntax in the SDK for Python (Boto3) documentation for CreateFeatureGroup, UpdateFeatureGroup, and PutRecord APIs.

  • When TtlDuration is applied at a feature group level (using the CreateFeatureGroup or UpdateFeatureGroup APIs), the applied TtlDuration becomes the default TtlDuration for all records that are added to the feature group from the point in time that the API is called. When applying TtlDuration with the UpdateFeatureGroup API, this will not become the default TtlDuration for records that were created before the API is called.

    To remove the default TtlDuration from an existing feature group, use the UpdateFeatureGroup API and set the TtlDuration Unit and Value to null.

  • When TtlDuration is applied at a record level (for example, using PutRecord API), the TtlDuration duration applies to that record and is used instead of the feature group level default TtlDuration.

  • When TtlDuration is applied on a feature group level it may take a few minutes for TtlDuration to come into effect.

  • If TtlDuration is used when there is no online store, you will receive a Validation Exception (400) error.

The following example code shows how to apply TtlDuration while updating a feature group, such that the records added to the feature group after running the API will by default expire four weeks after their event times.

import boto3

sagemaker_client = boto3.client("sagemaker")
feature_group_name = '<YOUR_FEATURE_GROUP_NAME>'

sagemaker_client.update_feature_group(
    FeatureGroupName=feature_group_name,
    OnlineStoreConfig={
        TtlDuration:{
            Unit: "Weeks",
            Value: 4
        }
    }
)

You can use the DescribeFeatureGroup API to view the default TtlDuration.

To view the expiration times, ExpiresAt (in UTC time ISO-8601 format), while using the GetRecord or BatchGetRecord APIs you must set ExpirationTimeResponse to ENABLED. See the request and response syntax in the SDK for Python (Boto3) documentation for DescribeFeatureGroup, GetRecord, and BatchGetRecord APIs.