MongoDB to ADLS
real-time replication
TwinCommit replicates MongoDB to Azure Data Lake Storage in real time by reading the MongoDB transaction log and applying every committed change exactly once and in commit order. Use it to land live MongoDB data in ADLS as open Delta Lake or Iceberg tables, with no triggers or capture tables on the source.
MongoDB
log reader
commit-ordered · exactly-once
ADLS
native writer
How capture works on MongoDB
TwinCommit opens change streams on replica sets and sharded clusters, persists resume tokens with the checkpoint, and keeps multi-document transactions intact.
Prerequisites
- ✓Replica set or sharded cluster (change streams need an oplog)
- ✓changeStream and find privileges on watched databases
- ✓Pre- and post-images enabled for full before/after values (optional)
How apply works on ADLS
Each micro-batch becomes one atomic Delta Lake or Apache Iceberg commit (or Parquet files) with the checkpoint stored in the commit itself. Use merge mode to mirror current state, or append mode for a full change history.
Requirements
- ✓Storage Blob Data Contributor on the container
- ✓Hierarchical namespace enabled
- ✓Optional Iceberg catalog (REST or Hive Metastore)
Setup
Set up MongoDB → ADLS in four steps
- 1
Prepare MongoDB
Run twincommit check. It verifies replica set or sharded cluster (change streams need an oplog) and the other prerequisites, and prints the exact fix for anything missing.
- 2
Point at ADLS
Add a target block for ADLS. TwinCommit can generate target DDL with twincommit ddl -apply.
- 3
Snapshot
twincommit snapshot copies each table under a brief share lock and records the exact log position.
- 4
Stream
twincommit run streams every committed change from that position, exactly once and in commit order.
source:
type: mongodb
uri: ${MONGODB_URI}
target:
type: adls
account: acmelake
container: lake
path: replica/{schema}/{table}
format: delta
mode: merge
tables:
- source: sales.orders
- source: sales.customersMongoDB to ADLS replication FAQ
How does TwinCommit replicate MongoDB to ADLS?
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TwinCommit reads changes from the MongoDB transaction log, buffers them per transaction, and applies each committed transaction to ADLS in commit order. Each micro-batch becomes one atomic Delta Lake or Apache Iceberg commit (or Parquet files) with the checkpoint stored in the commit itself. Use merge mode to mirror current state, or append mode for a full change history.
Does MongoDB to ADLS replication need triggers or capture tables?
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No. TwinCommit reads the MongoDB log directly and creates no objects in the source database.
Is MongoDB to ADLS replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same ADLS transaction as the data, so a crash or restart never loses or duplicates a transaction.
What MongoDB versions are supported?
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MongoDB 5.0–8.x · MongoDB Atlas · replica sets and sharded clusters.
Stream MongoDB to ADLS today.
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