PostgreSQL to SQL Server
real-time replication
TwinCommit replicates PostgreSQL to Microsoft SQL Server in real time by reading the PostgreSQL transaction log and applying every committed change exactly once and in commit order. Use it to migrate or continuously mirror PostgreSQL into SQL Server with zero downtime, with no triggers or capture tables on the source.
PostgreSQL
log reader
commit-ordered · exactly-once
SQL Server
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 SQL Server
Set-based MERGE into BIN2-collated tables with an in-transaction checkpoint.
Requirements
- ✓FULL recovery model
- ✓Primary key on each replicated table
- ✓VIEW SERVER STATE and db_owner on the source database
Setup
Set up PostgreSQL → SQL Server 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 SQL Server
Add a target block for SQL Server. 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: sqlserver
dsn: ${MSSQL_DSN}
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]PostgreSQL to SQL Server replication FAQ
How does TwinCommit replicate PostgreSQL to SQL Server?
+
TwinCommit reads changes from the PostgreSQL transaction log, buffers them per transaction, and applies each committed transaction to SQL Server in commit order. Set-based MERGE into BIN2-collated tables with an in-transaction checkpoint.
Does PostgreSQL to SQL Server replication need triggers or capture tables?
+
No. TwinCommit reads the PostgreSQL log directly and creates no objects in the source database.
Is PostgreSQL to SQL Server replication exactly-once?
+
Yes. TwinCommit commits its checkpoint in the same SQL Server 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 SQL Server today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.