# MongoDB ## Description The [MongoDB](https://www.mongodb.com/) online store provides support for materializing feature values into MongoDB for serving online features. ## Features * Supports both synchronous and asynchronous operations for high-performance feature retrieval * Native async support uses PyMongo's `AsyncMongoClient` (no Motor dependency required) * Flexible connection options supporting MongoDB Atlas, self-hosted MongoDB, and MongoDB replica sets * Automatic index creation for optimized query performance * Entity key collocation for efficient feature retrieval ## Getting started In order to use this online store, you'll need to install the MongoDB extra (along with the dependency needed for the offline store of choice): ```bash pip install 'feast[mongodb]' ``` You can get started by using any of the other templates (e.g. `feast init -t gcp` or `feast init -t snowflake` or `feast init -t aws`), and then swapping in MongoDB as the online store as seen below in the examples. ## Examples ### Basic configuration with MongoDB Atlas {% code title="feature\_store.yaml" %} ```yaml project: my_feature_repo registry: data/registry.db provider: local online_store: type: mongodb connection_string: "mongodb+srv://username:password@cluster.mongodb.net/" # pragma: allowlist secret database_name: feast_online_store ``` {% endcode %} ### Self-hosted MongoDB with authentication {% code title="feature\_store.yaml" %} ```yaml project: my_feature_repo registry: data/registry.db provider: local online_store: type: mongodb connection_string: "mongodb://username:password@localhost:27017/" # pragma: allowlist secret database_name: feast_online_store collection_suffix: features ``` {% endcode %} ### MongoDB replica set configuration {% code title="feature\_store.yaml" %} ```yaml project: my_feature_repo registry: data/registry.db provider: local online_store: type: mongodb connection_string: "mongodb://host1:27017,host2:27017,host3:27017/?replicaSet=myReplicaSet" database_name: feast_online_store client_kwargs: retryWrites: true w: majority ``` {% endcode %} ### Advanced configuration with custom client options {% code title="feature\_store.yaml" %} ```yaml project: my_feature_repo registry: data/registry.db provider: local online_store: type: mongodb connection_string: "mongodb+srv://cluster.mongodb.net/" database_name: feast_online_store collection_suffix: features client_kwargs: maxPoolSize: 50 minPoolSize: 10 serverSelectionTimeoutMS: 5000 connectTimeoutMS: 10000 ``` {% endcode %} The full set of configuration options is available in [MongoDBOnlineStoreConfig](https://rtd.feast.dev/en/latest/#feast.infra.online_stores.mongodb_online_store.mongodb.MongoDBOnlineStoreConfig). ## Data Model The MongoDB online store uses a **single collection per project** with entity key collocation. Features from multiple feature views for the same entity are stored together in a single document. ### Example Document Schema The example shows a single entity. It contains 3 features from 2 feature views: "rating" and "trips\_last7d" from Feature View "driver\_stats", and "surge\_multiplier" from "pricing" view. Each feature view has its own event timestamp. The "created\_timestamp" marks when the entity was materialized. ```javascript { "_id": "", // Binary entity key (bytes) "features": { "driver_stats": { "rating": 4.91, "trips_last_7d": 132 }, "pricing": { "surge_multiplier": 1.2 } }, "event_timestamps": { "driver_stats": ISODate("2026-01-20T12:00:00Z"), "pricing": ISODate("2026-01-21T08:30:00Z") }, "created_timestamp": ISODate("2026-01-21T12:00:05Z") } ``` ### Key Design Decisions * **`_id` field**: Uses the serialized entity key (bytes) as the primary key for efficient lookups * **Nested features**: Features are organized by feature view name, allowing multiple feature views per entity * **Event timestamps**: Stored per feature view to track when each feature set was last updated * **Created timestamp**: Global timestamp for the entire document ### Indexes The online store automatically creates the following index: * Primary key index on `_id` (automatic in MongoDB), set to the serialized entity key. No additional indexes are required for the online store operations. ## Async Support The MongoDB online store provides native async support using PyMongo 4.13+'s stable `AsyncMongoClient`. This enables: * **High concurrency**: Handle thousands of concurrent feature requests without thread pool limitations * **True async I/O**: Non-blocking operations for better performance in async applications * **10-20x performance improvement**: For concurrent workloads compared to sequential sync operations Both sync and async methods are fully supported: * `online_read` / `online_read_async` * `online_write_batch` / `online_write_batch_async` ## Functionality Matrix The set of functionality supported by online stores is described in detail [here](/master/reference/online-stores/overview.md#functionality). Below is a matrix indicating which functionality is supported by the MongoDB online store. | | MongoDB | | --------------------------------------------------------- | ------- | | write feature values to the online store | yes | | read feature values from the online store | yes | | update infrastructure (e.g. tables) in the online store | yes | | teardown infrastructure (e.g. tables) in the online store | yes | | generate a plan of infrastructure changes | no | | support for on-demand transforms | yes | | readable by Python SDK | yes | | readable by Java | no | | readable by Go | no | | support for entityless feature views | yes | | support for concurrent writing to the same key | yes | | support for ttl (time to live) at retrieval | no | | support for deleting expired data | no | | collocated by feature view | no | | collocated by feature service | no | | collocated by entity key | yes | To compare this set of functionality against other online stores, please see the full [functionality matrix](/master/reference/online-stores/overview.md#functionality-matrix). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.feast.dev/master/reference/online-stores/mongodb.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.