PostgreSQL to Redis
real-time replication
TwinCommit replicates PostgreSQL to Redis in real time by reading the PostgreSQL transaction log and applying every committed change exactly once and in commit order. Use it to keep a Redis cache exactly in sync with PostgreSQL, with no triggers or capture tables on the source.
PostgreSQL
log reader
commit-ordered · exactly-once
Redis
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 Redis
Each row is written as a Redis hash (or JSON document) under a key template such as `orders:{ORDER_ID}`, with deletes removing the key. Optionally every change is also appended to a Redis Stream.
Requirements
- ✓A key template per table
- ✓ACL user with write access to the key prefix
- ✓TLS endpoint recommended
Setup
Set up PostgreSQL → Redis 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 Redis
Add a target block for Redis. 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: redis
url: rediss://cache.internal:6380
key_template: "{table}:{pk}"
format: hash
tables:
- source: SALES.ORDERS
- source: SALES.ORDER_LINES
exclude_columns: [INTERNAL_NOTES]PostgreSQL to Redis replication FAQ
How does TwinCommit replicate PostgreSQL to Redis?
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TwinCommit reads changes from the PostgreSQL transaction log, buffers them per transaction, and applies each committed transaction to Redis in commit order. Each row is written as a Redis hash (or JSON document) under a key template such as orders:{ORDER_ID}, with deletes removing the key. Optionally every change is also appended to a Redis Stream.
Does PostgreSQL to Redis 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 Redis replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same Redis 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.
Use cases for this route
Related replication routes
Stream PostgreSQL to Redis today.
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