SQL Server to ADLS
real-time replication
TwinCommit replicates Microsoft SQL Server to Azure Data Lake Storage in real time by reading the SQL Server transaction log and applying every committed change exactly once and in commit order. Use it to land live SQL Server data in ADLS as open Delta Lake or Iceberg tables, with no triggers or capture tables on the source.
SQL Server
log reader
commit-ordered · exactly-once
ADLS
native writer
How capture works on SQL Server
TwinCommit reads the active and backed-up transaction log directly, so you do not need SQL Server Agent CDC jobs or change tables.
Prerequisites
- ✓FULL recovery model
- ✓Primary key on each replicated table
- ✓VIEW SERVER STATE and db_owner on the source database
How apply works on ADLS
Each micro-batch becomes one atomic Delta Lake or Apache Iceberg commit (or Parquet files) with the checkpoint stored in the commit itself. Use merge mode to mirror current state, or append mode for a full change history.
Requirements
- ✓Storage Blob Data Contributor on the container
- ✓Hierarchical namespace enabled
- ✓Optional Iceberg catalog (REST or Hive Metastore)
Setup
Set up SQL Server → ADLS in four steps
- 1
Prepare SQL Server
Run twincommit check. It verifies full recovery model and the other prerequisites, and prints the exact fix for anything missing.
- 2
Point at ADLS
Add a target block for ADLS. 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: sqlserver
dsn: ${SOURCE_DSN}
target:
type: adls
account: acmelake
container: lake
path: replica/{schema}/{table}
format: delta
mode: merge
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]SQL Server to ADLS replication FAQ
How does TwinCommit replicate SQL Server to ADLS?
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TwinCommit reads changes from the SQL Server transaction log, buffers them per transaction, and applies each committed transaction to ADLS in commit order. Each micro-batch becomes one atomic Delta Lake or Apache Iceberg commit (or Parquet files) with the checkpoint stored in the commit itself. Use merge mode to mirror current state, or append mode for a full change history.
Does SQL Server to ADLS replication need triggers or capture tables?
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No. TwinCommit reads the SQL Server log directly and creates no objects in the source database.
Is SQL Server to ADLS replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same ADLS transaction as the data, so a crash or restart never loses or duplicates a transaction.
What SQL Server versions are supported?
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SQL Server 2016–2025 · Azure SQL Managed Instance · Azure SQL Database (target).
Stream SQL Server to ADLS today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.