MongoDB to Oracle
real-time replication
TwinCommit replicates MongoDB to Oracle Database in real time by reading the MongoDB transaction log and applying every committed change exactly once and in commit order. Use it to migrate or continuously mirror MongoDB into Oracle with zero downtime, with no triggers or capture tables on the source.
MongoDB
log reader
commit-ordered · exactly-once
Oracle
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 Oracle
Array-bound MERGE statements committed together with the TwinCommit checkpoint table in one transaction.
Requirements
- ✓ARCHIVELOG mode
- ✓Minimal plus primary-key supplemental logging
- ✓Read access to V$ views and the archive destination
Setup
Set up MongoDB → Oracle 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 Oracle
Add a target block for Oracle. 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: oracle
dsn: ${ORACLE_TARGET_DSN}
schema: REPLICA
tables:
- source: sales.orders
- source: sales.customersMongoDB to Oracle replication FAQ
How does TwinCommit replicate MongoDB to Oracle?
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TwinCommit reads changes from the MongoDB transaction log, buffers them per transaction, and applies each committed transaction to Oracle in commit order. Array-bound MERGE statements committed together with the TwinCommit checkpoint table in one transaction.
Does MongoDB to Oracle 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 Oracle replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same Oracle 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 Oracle today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.