PostgreSQL to Db2
real-time replication
TwinCommit replicates PostgreSQL to IBM Db2 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 Db2 with zero downtime, with no triggers or capture tables on the source.
PostgreSQL
log reader
commit-ordered · exactly-once
Db2
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 Db2
Array MERGE statements committed in the same unit of work as the TwinCommit checkpoint.
Requirements
- ✓Archive logging enabled (LOGARCHMETH1)
- ✓DATA CAPTURE CHANGES on each replicated table
- ✓A primary key or unique index on each replicated table
- ✓DBADM (or SYSADM) for the capture user
Setup
Set up PostgreSQL → Db2 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 Db2
Add a target block for Db2. 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: db2
database: REPLDB
user: ${DB2_TARGET_USER}
password: ${DB2_TARGET_PASSWORD}
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]PostgreSQL to Db2 replication FAQ
How does TwinCommit replicate PostgreSQL to Db2?
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TwinCommit reads changes from the PostgreSQL transaction log, buffers them per transaction, and applies each committed transaction to Db2 in commit order. Array MERGE statements committed in the same unit of work as the TwinCommit checkpoint.
Does PostgreSQL to Db2 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 Db2 replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same Db2 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 Db2 today.
Download the free Developer edition, or have one of our replication engineers walk you through a migration plan.