Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Create a dataset from your feature groups

After a Feature Store feature group has been created in an offline store, you can choose to use the following methods to get your data:

After you've created feature groups for your offline store and populated them with data, you can create a dataset by running queries or using the SDK to join data stored in the offline store from different feature groups. You can also join the feature groups to a single pandas dataframe. You can use Amazon Athena to write and execute SQL queries.

Using the Amazon SageMaker Python SDK to get your data from your feature groups

You can use the Feature Store APIs to create a dataset from your feature groups. Data scientists create ML datasets for training by retrieving ML feature data from one or more feature groups in the offline store. Use the create_dataset() function to create the dataset. You can use the SDK to do the following:

By default, Feature Store doesn't include records that you've deleted from the dataset. It also doesn't include duplicated records. A duplicate record has the record ID and timestamp value in the event time column.

Before you use the SDK to create a dataset, you must start a SageMaker session. Use the following code to start the session.

import boto3
from sagemaker.session import Session
from sagemaker.feature_store.feature_store import FeatureStore

region = boto3.Session().region_name
boto_session = boto3.Session(region_name=region)

sagemaker_client = boto_session.client(
    service_name="sagemaker", region_name=region
 )
featurestore_runtime = boto_session.client(
    service_name="sagemaker-featurestore-runtime",region_name=region
)

feature_store_session = Session(
    boto_session=boto_session,
    sagemaker_client=sagemaker_client,
    sagemaker_featurestore_runtime_client=featurestore_runtime,
)

feature_store = FeatureStore(feature_store_session) 

The following code shows an example of creating a dataset from multiple feature groups. The following code snippet uses the example feature groups "base_fg_name", "first_fg_name", and "second_fg_name", which may not exist or have the same schema within your Feature Store. It is recommended to replace these feature groups with feature groups that exist within your Feature Store. For information on how to create a feature group, see Step 3: Create feature groups.

from sagemaker.feature_store.feature_group import FeatureGroup

s3_bucket_name = "offline-store-sdk-test" 

base_fg_name = "base_fg_name"
base_fg = FeatureGroup(name=base_fg_name, sagemaker_session=feature_store_session)

first_fg_name = "first_fg_name"
first_fg = FeatureGroup(name=first_fg_name, sagemaker_session=feature_store_session)

second_fg_name = "second_fg_name"
second_fg = FeatureGroup(name=second_fg_name, sagemaker_session=feature_store_session)

feature_store = FeatureStore(feature_store_session)
builder = feature_store.create_dataset(
    base=base_fg,
    output_path=f"s3://{DOC-EXAMPLE-BUCKET1}",
).with_feature_group(first_fg
).with_feature_group(second_fg, "base_id", ["base_feature_1"])         
        

The following code shows an example of creating a dataset from multiple feature groups and a pandas dataframe.

base_data = [[1, 187512346.0, 123, 128],
             [2, 187512347.0, 168, 258],
             [3, 187512348.0, 125, 184],
             [1, 187512349.0, 195, 206]]
base_data_df = pd.DataFrame(
    base_data, 
    columns=["base_id", "base_time", "base_feature_1", "base_feature_2"]
)

builder = feature_store.create_dataset(
    base=base_data_df, 
    event_time_identifier_feature_name='base_time', 
    record_identifier_feature_name='base_id',
    output_path=f"s3://{s3_bucket_name}"
).with_feature_group(first_fg
).with_feature_group(second_fg, "base_id", ["base_feature_1"])            
        

The Feature Store APIs provides you with helper methods for the create_dataset function. You can use them to do the following:

The base feature group is an important concept for joins. The base feature group is the feature group that has other feature groups or the pandas dataframe joined to it. For each dataset

You can add the following optional methods to the create_dataset function to configure how you're creating dataset:

After you've configured the dataset, you can specify the output using one of the following methods:

You can retrieve data that comes after a specific period in time. The following code retrieves data after a timestamp.

fg1 = FeatureGroup("example-feature-group-1")
feature_store.create_dataset(
    base=fg1, 
    output_path="s3://example-S3-path"
).with_number_of_records_from_query_results(5).to_csv_file()  

You can also retrieve data from a specific time period. You can use the following code to get data for a specific time range:

fg1 = FeatureGroup("fg1")
feature_store.create_dataset(
    base=fg1, 
    output_path="example-S3-path"
).with_event_time_range(
    datetime(2021, 11, 28, 23, 55, 59, 342380), 
    datetime(2020, 11, 28, 23, 55, 59, 342380)
).to_csv_file() #example time range specified in datetime functions

You might want to join multiple feature groups to a pandas dataframe where the event time values of the feature group happen no later than the event time of the data frame. Use the following code as a template to help you perform the join.

fg1 = FeatureGroup("fg1")
fg2 = FeatureGroup("fg2")
events = [['2020-02-01T08:30:00Z', 6, 1],
          ['2020-02-02T10:15:30Z', 5, 2],
          ['2020-02-03T13:20:59Z', 1, 3],
          ['2021-01-01T00:00:00Z', 1, 4]]
df = pd.DataFrame(events, columns=['event_time', 'customer-id', 'title-id']) 
feature_store.create_dataset(
    base=df, 
    event_time_identifier_feature_name='event_time', 
    record_identifier_feature_name='customer_id',
    output_path="s3://example-S3-path"
).with_feature_group(fg1, "customer-id"
).with_feature_group(fg2, "title-id"
).point_in_time_accurate_join(
).to_csv_file()

You can also retrieve data that comes after a specific period in time. The following code retrieves data after the time specified by the timestamp in the as_of method.

fg1 = FeatureGroup("fg1")
feature_store.create_dataset(
    base=fg1, 
    output_path="s3://example-s3-file-path"
).as_of(datetime(2021, 11, 28, 23, 55, 59, 342380)
).to_csv_file() # example datetime values

Sample Amazon Athena queries

You can write queries in Amazon Athena to create a dataset from your feature groups. You can also write queries that create a dataset from feature groups and a single pandas dataframe.

Interactive Exploration

This query selects the first 1000 records. 

SELECT *
FROM <FeatureGroup.DataCatalogConfig.DatabaseName>.<FeatureGroup.DataCatalogConfig.TableName>
LIMIT 1000

Latest snapshot without duplicates

This query selects the latest non-duplicate records.

SELECT *
FROM
    (SELECT *,
         row_number()
        OVER (PARTITION BY <RecordIdentiferFeatureName>
    ORDER BY  <EventTimeFeatureName> desc, Api_Invocation_Time DESC, write_time DESC) AS row_num
    FROM <FeatureGroup.DataCatalogConfig.DatabaseName>.<FeatureGroup.DataCatalogConfig.TableName>)
WHERE row_num = 1;

Latest snapshot without duplicates and deleted records in the offline store

This query filters out any deleted records and selects non-duplicate records from the offline store. 

SELECT *
FROM
    (SELECT *,
         row_number()
        OVER (PARTITION BY <RecordIdentiferFeatureName>
    ORDER BY  <EventTimeFeatureName> desc, Api_Invocation_Time DESC, write_time DESC) AS row_num
    FROM <FeatureGroup.DataCatalogConfig.DatabaseName>.<FeatureGroup.DataCatalogConfig.TableName>)
WHERE row_num = 1 and 
NOT is_deleted;

Time Travel without duplicates and deleted records in the offline store

This query filters out any deleted records and selects non-duplicate records from a particular point in time.

SELECT *
FROM
    (SELECT *,
         row_number()
        OVER (PARTITION BY <RecordIdentiferFeatureName>
    ORDER BY  <EventTimeFeatureName> desc, Api_Invocation_Time DESC, write_time DESC) AS row_num
    FROM <FeatureGroup.DataCatalogConfig.DatabaseName>.<FeatureGroup.DataCatalogConfig.TableName>
    where <EventTimeFeatureName> <= timestamp '<timestamp>')
    -- replace timestamp '<timestamp>' with just <timestamp>  if EventTimeFeature is of type fractional
WHERE row_num = 1 and
NOT is_deleted