18.4 Replication & Persistence
1. Why replicate
Replication moves the runtime dependency from the source toward a local persisted representation.
Source
|
replication
|
local table
|
semantic model
|
consumer
This can improve:
- source protection,
- query consistency,
- analytics performance,
- recovery,
- reuse.
2. Full versus delta
A replication design must define:
- initial load,
- delta mechanism,
- deletion handling,
- restart behavior,
- retention,
- reconciliation.
SAP Datasphere replication flows support delta loads for supported source connections.
3. Freshness model
Define freshness as a measurable contract.
Example:
Source commit
|
+-- extraction delay
|
+-- transfer delay
|
+-- target commit
|
+-- semantic availability
|
consumer freshness
4. Persistence placement
Do not persist every intermediate dataset.
Persist where it provides:
- performance,
- reuse,
- isolation,
- recovery,
- governance,
- historical value.
5. Storage optimization
For large datasets evaluate:
- unnecessary columns,
- filters,
- partitioning where supported,
- in-memory acceleration where appropriate,
- retention,
- incremental processing.
SAP documentation explicitly recommends filtering unnecessary columns and data during acquisition and transformation.
6. Reconciliation
At minimum compare:
- source record count,
- target record count,
- business totals,
- latest source timestamp,
- latest target timestamp,
- rejected records.
Exercise
Design a daily 2 TB replication pipeline with a 15-minute freshness SLA.
Explain initial load, delta, recovery, reconciliation and cost controls.