PostgreSQL to Kafka
real-time replication
TwinCommit replicates PostgreSQL to Apache Kafka in real time by reading the PostgreSQL transaction log and applying every committed change exactly once and in commit order. Use it to publish every committed PostgreSQL change as an event stream, with no triggers or capture tables on the source.
PostgreSQL
log reader
commit-ordered · exactly-once
Kafka
native writer
How capture works on PostgreSQL
TwinCommit uses a logical replication slot with the built-in pgoutput plugin, so there is nothing to install on the server.
Prerequisites
- ✓wal_level = logical
- ✓REPLICATION privilege
- ✓Primary key or REPLICA IDENTITY FULL
How apply works on Kafka
Each source transaction is published with Kafka transactions, so consumers using read_committed never see a partial transaction. Messages are keyed by primary key in JSON, Avro or Protobuf.
Requirements
- ✓A topic naming template
- ✓Producer ACLs including transactional.id
- ✓Optional Schema Registry for Avro and Protobuf
Setup
Set up PostgreSQL → Kafka in four steps
- 1
Prepare PostgreSQL
Run twincommit check. It verifies wal_level = logical and the other prerequisites, and prints the exact fix for anything missing.
- 2
Point at Kafka
Add a target block for Kafka. 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: postgres
dsn: ${SOURCE_DSN}
slot: twincommit
target:
type: kafka
bootstrap_servers: broker-1:9092,broker-2:9092
topic: "{schema}.{table}"
format: avro
schema_registry: http://registry:8081
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]PostgreSQL to Kafka replication FAQ
How does TwinCommit replicate PostgreSQL to Kafka?
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TwinCommit reads changes from the PostgreSQL transaction log, buffers them per transaction, and applies each committed transaction to Kafka in commit order. Each source transaction is published with Kafka transactions, so consumers using read_committed never see a partial transaction. Messages are keyed by primary key in JSON, Avro or Protobuf.
Does PostgreSQL to Kafka replication need triggers or capture tables?
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No. TwinCommit reads the PostgreSQL log directly and creates no objects in the source database.
Is PostgreSQL to Kafka replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same Kafka transaction as the data, so a crash or restart never loses or duplicates a transaction.
What PostgreSQL versions are supported?
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PostgreSQL 13–18 · Amazon RDS and Aurora · Azure Flexible Server · Cloud SQL · AlloyDB.
Stream PostgreSQL to Kafka today.
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