Functionality

Here are the methods exposed by the OnlineStore interface, along with the core functionality supported by the method:

• online_write_batch: write feature values to the online store

• online_read: read feature values from the online store

• update: update infrastructure (e.g. tables) in the online store

• teardown: teardown infrastructure (e.g. tables) in the online store

• plan: generate a plan of infrastructure changes based on feature repo changes

There is also additional functionality not properly captured by these interface methods:

• support for on-demand transforms

• readable by Python SDK

• readable by Java

• readable by Go

• support for entityless feature views

• support for concurrent writing to the same key

• support for ttl (time to live) at retrieval

• support for deleting expired data

Finally, there are multiple data models for storing the features in the online store. For example, features could be:

• collocated by feature view

• collocated by feature service

• collocated by entity key

See this issue for a discussion around the tradeoffs of each of these data models.

Functionality Matrix

Below is a matrix indicating which online stores support what functionality.

Description

The SQLite online store provides support for materializing feature values into an SQLite database for serving online features.

• All feature values are stored in an on-disk SQLite database

• Only the latest feature values are persisted

Example

The full set of configuration options is available in SqliteOnlineStoreConfig.

Functionality Matrix

Description

• Only the latest feature values are persisted

The data model for using a Snowflake Transient Table as an online store follows a tall format (one row per feature)):

• "entity_feature_key" (BINARY) -- unique key used when reading specific feature_view x entity combination

• "entity_key" (BINARY) -- repeated key currently unused for reading entity_combination

• "feature_name" (VARCHAR)

• "value" (BINARY)

• "event_ts" (TIMESTAMP)

• "created_ts" (TIMESTAMP)

(This model may be subject to change when Snowflake Hybrid Tables are released)

Getting started

In order to use this online store, you'll need to run pip install 'feast[snowflake]'. You can then get started with the command feast init REPO_NAME -t snowflake.

Example

Tags KWARGs Actions:

"snowflake-online-store/online_path": Adding the "snowflake-online-store/online_path" key to a FeatureView tags parameter allows you to choose the online table path for the online serving table (ex. "{database}"."{schema}").

Functionality Matrix