Oracle to SQL Server
real-time replication
TwinCommit replicates Oracle Database to Microsoft SQL Server in real time by reading the Oracle transaction log and applying every committed change exactly once and in commit order. Use it to migrate or continuously mirror Oracle into SQL Server with zero downtime, with no triggers or capture tables on the source.
Oracle
log reader
commit-ordered · exactly-once
SQL Server
native writer
How capture works on Oracle
TwinCommit parses online redo and archived logs directly, including RAC threads, and reassembles transactions in SCN order before they leave the host.
Prerequisites
- ✓ARCHIVELOG mode
- ✓Minimal plus primary-key supplemental logging
- ✓Read access to V$ views and the archive destination
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 Oracle → SQL Server in four steps
- 1
Prepare Oracle
Run twincommit check. It verifies archivelog mode 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: oracle
database: PRODDB
user: ${SRC_USER}
password: ${SRC_PASSWORD}
target:
type: sqlserver
dsn: ${MSSQL_DSN}
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]Oracle to SQL Server replication FAQ
How does TwinCommit replicate Oracle to SQL Server?
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TwinCommit reads changes from the Oracle 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 Oracle to SQL Server replication need triggers or capture tables?
+
No. TwinCommit reads the Oracle log directly and creates no objects in the source database.
Is Oracle to SQL Server replication exactly-once?
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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 Oracle versions are supported?
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Oracle 19c, 21c, 23ai · RAC, Data Guard standby, CDB/PDB · Autonomous Database (target).
Stream Oracle to SQL Server today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.