MySQL to MongoDB
real-time replication
TwinCommit replicates MySQL to MongoDB in real time by reading the MySQL transaction log and applying every committed change exactly once and in commit order. Use it to serve MySQL data from MongoDB at scale without dual writes, with no triggers or capture tables on the source.
MySQL
log reader
commit-ordered · exactly-once
MongoDB
native writer
How capture works on MySQL
TwinCommit connects as a replica, reads the row-based binary log and tracks position by GTID, so failovers and replica promotions are seamless.
Prerequisites
- ✓binlog_format = ROW and binlog_row_image = FULL
- ✓GTID mode recommended
- ✓REPLICATION SLAVE and REPLICATION CLIENT grants
How apply works on MongoDB
Relational rows become documents keyed by primary key and are written with bulkWrite upserts inside MongoDB transactions, together with the checkpoint.
Requirements
- ✓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)
Setup
Set up MySQL → MongoDB in four steps
- 1
Prepare MySQL
Run twincommit check. It verifies binlog_format = row and binlog_row_image = full and the other prerequisites, and prints the exact fix for anything missing.
- 2
Point at MongoDB
Add a target block for MongoDB. 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: mysql
dsn: ${SOURCE_DSN}
server_id: 4201
target:
type: mongodb
uri: ${MONGODB_URI}
database: replica
document_id: primary_key
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]MySQL to MongoDB replication FAQ
How does TwinCommit replicate MySQL to MongoDB?
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TwinCommit reads changes from the MySQL transaction log, buffers them per transaction, and applies each committed transaction to MongoDB in commit order. Relational rows become documents keyed by primary key and are written with bulkWrite upserts inside MongoDB transactions, together with the checkpoint.
Does MySQL to MongoDB replication need triggers or capture tables?
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No. TwinCommit reads the MySQL log directly and creates no objects in the source database.
Is MySQL to MongoDB replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same MongoDB transaction as the data, so a crash or restart never loses or duplicates a transaction.
What MySQL versions are supported?
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MySQL 5.7, 8.0, 8.4, 9.x · Amazon RDS & Aurora MySQL · Azure Database for MySQL · Cloud SQL.
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