title: 'MongoDB Data Connector'
sidebar_label: 'MongoDB Data Connector'
description: 'MongoDB Data Connector Documentation'
tags:
MongoDB is an open-source NoSQL database that stores data in flexible, JSON-like documents, supporting dynamic schemas and easy scalability.
The MongoDB Data Connector enables federated/accelerated SQL queries on data stored in MongoDB databases.
Configuration
from
The from field takes the form mongodb:{table_name} where table_name is the table identifer in the MongoDB server to read from.
:::info
Unquoted identifiers are normalized to lowercase. To reference a collection with mixed-case characters, wrap it in double quotes: mongodb:"MixedCaseCollection". See Identifier Case Sensitivity.
:::
name
The dataset name. This will be used as the table name within Spice.
Example:
The dataset name cannot be a reserved keyword
params
The MongoDB data connector can be configured by providing the following params. Use the secret replacement syntax to load the secret from a secret store, e.g. ${secrets:my_mongodb_conn_string}.
| Parameter Name | Description |
|---|
mongodb_connection_string | The connection string to use to connect to the MongoDB server. This can be used instead of providing individual connection parameters. |
mongodb_user | The MongoDB username. |
mongodb_pass | The password to connect with. |
mongodb_host | The hostname of the MongoDB server. Defaults to localhost. |
mongodb_port | The port of the MongoDB server. Defaults to 27017. |
mongodb_db | The name of the database to connect to. Defaults to default. |
mongodb_sslmode | Optional. Specifies the SSL/TLS behavior for the connection, supported values: required: (default) This mode requires an SSL connection. If a secure connection cannot be established, server will not connect.preferred: Establishes an encrypted TLS/SSL connection but does not validate the server certificate or hostname (accepts invalid or self-signed certificates). If the server does not support TLS, the connection fails; it is never downgraded to plaintext.: This mode will not attempt to use an SSL connection, even if the server supports it. |
Types
The table below shows the MongoDB data types supported, along with the type mapping to Apache Arrow types in Spice.
| MongoDB Type | Arrow Type |
|---|
String | Utf8 |
Boolean | Boolean |
Int32 | Int32 |
Int64 | Int64 |
Double | Float64 |
Decimal128 | Decimal128 |
Binary | Binary |
Datetime without time | Date32 |
Datetime with time |
:::note
- The MongoDB
Datetime value is retrieved as a UTC time value by default. Use the mongodb_time_zone configuration parameter to specify the desired time zone for interpreting TIMESTAMP values during data retrieval.
:::
Unnesting
Consider the following document:
Using mongodb_unnest_depth you can control the unnesting behavior. Here are the examples:
mongodb_unnest_depth: 0
mongodb_unnest_depth: 1
mongodb_unnest_depth: 2
Examples
Connecting using username and password and custom auth table
Connecting using SSL
Connecting using a Connection String
Connecting to MongoDB Atlas (SRV)
When mongodb_host ends with .mongodb.net, mongodb_srv is automatically enabled and mongodb_port is ignored — mongodb+srv:// discovers host/port via DNS SRV records.
Set mongodb_srv: true explicitly for non-Atlas hosts that are configured with SRV records:
With custom connection pool settings
Using MongoDB Change Streams
Spice supports real-time Change Data Capture (CDC) from MongoDB using native MongoDB Change Streams. This streams inserts, updates, replacements, deletes, and collection-level invalidation events from MongoDB collections directly into Spice accelerators.
How it works
On startup, Spice opens a Change Stream on the source collection (fullDocument=updateLookup), emits a CDC TRUNCATE, applies a full snapshot of the collection as upsert rows, signals readiness, then processes Change Stream events in batches. Opening the Change Stream before the snapshot prevents gaps between the snapshot and the live stream.
File-accelerated datasets persist resume tokens and resume from the last committed token on restart. In-memory accelerators re-bootstrap from a fresh snapshot.
Prerequisites
- MongoDB 4.0+ with Change Streams enabled. MongoDB requires a replica set or sharded cluster for Change Streams.
- The MongoDB user must have
changeStream privileges.
- The accelerator must support upsert behavior. Use
duckdb, sqlite, postgres, turso, or cayenne.
acceleration.primary_key: _id is required. Delete events only include the document key, so Spice needs _id to route deletes.acceleration.on_conflict must specify upsert on _id so update and replace events overwrite existing rows.
Minimal configuration
Change Stream parameters
These optional runtime parameters live under dataset params:. The first four are not prefixed with mongodb_.
| Parameter Name | Default | Description |
|---|
change_stream_batch_max_size | 1000 | Maximum number of Change Stream events to group into one CDC batch before applying it. Must be greater than 0. |
change_stream_batch_max_duration | 1s | Maximum time to wait for a Change Stream batch to fill before applying it. Accepts fundu duration strings; must be greater than 0. |
change_stream_max_await_time | 1s | Maximum time MongoDB waits for new Change Stream events before returning an empty server batch. Accepts fundu duration strings; must be greater than 0. |
change_stream_batch_size | 1000 | Number of Change Stream events MongoDB should request from the server per batch. Must fit in a u32 and be greater than 0. |
mongodb_resume_token_invalid_behavior | error | Behavior when a persisted Change Stream resume token cannot be honored by the server (e.g. the token is past the oplog retention window). surfaces a clear error so the operator can decide; drops the persisted token and re-snapshots the collection. |
The existing mongodb_unnest_depth parameter also applies to Change Stream documents, so nested BSON is flattened the same way as normal MongoDB reads.
Event mapping
insert: create/upsert, using fullDocument.update: update/upsert, using fullDocument from fullDocument=updateLookup.replace: update/upsert, using fullDocument.delete: delete, using documentKey; non-key columns are null.drop, rename, dropDatabase, invalidate: truncate, because collection continuity is no longer guaranteed.
If MongoDB does not include fullDocument for an update or replace event, Spice fails the stream with a clear error instead of applying a partial row.
Resumability across restarts
For file-accelerated datasets (acceleration mode: file / file_create / file_update, or engine: postgres), Spice persists the most recent Change Stream resume token in a sidecar table named spice_sys_mongodb, stored alongside the accelerator data. The token is committed only after the downstream accelerator write succeeds (at-least-once semantics).
On restart with a persisted token, Spice resumes the Change Stream from that token and skips the collection snapshot. If MongoDB rejects the token (typical codes ChangeStreamHistoryLost 286 or ChangeStreamFatalError 280, e.g. when the oplog window has rolled past the token's position), the behavior is governed by mongodb_resume_token_invalid_behavior above. Re-snapshotting a large collection is opt-in by default.
Datasets that are not file-accelerated (in-memory Arrow, etc.) do not get a sidecar row; restarts re-bootstrap from a fresh snapshot.
Secrets
Spice integrates with multiple secret stores to help manage sensitive data securely. For detailed information on supported secret stores, refer to the secret stores documentation. Additionally, learn how to use referenced secrets in component parameters by visiting the using referenced secrets guide.
Cookbook
