PostgreSQL to S3
real-time replication
TwinCommit replicates PostgreSQL to Amazon S3 in real time by reading the PostgreSQL transaction log and applying every committed change exactly once and in commit order. Use it to land live PostgreSQL data in S3 as open Delta Lake or Iceberg tables, with no triggers or capture tables on the source.
PostgreSQL
log reader
commit-ordered · exactly-once
S3
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 S3
Changes land as Apache Iceberg, Delta Lake or Parquet tables, one atomic commit per micro-batch with the checkpoint in the snapshot metadata. Iceberg tables register in AWS Glue or Amazon S3 Tables automatically.
Requirements
- ✓IAM role with s3:GetObject, PutObject, DeleteObject and ListBucket on the prefix
- ✓Glue catalog permissions for table registration
- ✓Same-region placement recommended
Setup
Set up PostgreSQL → S3 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 S3
Add a target block for S3. 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: s3
bucket: acme-lake
path: replica/{schema}/{table}
format: iceberg
catalog: { type: glue, database: replica }
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]PostgreSQL to S3 replication FAQ
How does TwinCommit replicate PostgreSQL to S3?
+
TwinCommit reads changes from the PostgreSQL transaction log, buffers them per transaction, and applies each committed transaction to S3 in commit order. Changes land as Apache Iceberg, Delta Lake or Parquet tables, one atomic commit per micro-batch with the checkpoint in the snapshot metadata. Iceberg tables register in AWS Glue or Amazon S3 Tables automatically.
Does PostgreSQL to S3 replication need triggers or capture tables?
+
No. TwinCommit reads the PostgreSQL log directly and creates no objects in the source database.
Is PostgreSQL to S3 replication exactly-once?
+
Yes. TwinCommit commits its checkpoint in the same S3 transaction as the data, so a crash or restart never loses or duplicates a transaction.
What PostgreSQL versions are supported?
+
PostgreSQL 13–18 · Amazon RDS and Aurora · Azure Flexible Server · Cloud SQL · AlloyDB.
Stream PostgreSQL to S3 today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.