Understanding SAP HANA Smart Data Access (SDA): Ex...

Introduction
SAP HANA Smart Data Access (SDA) enables SAP HANA to access data stored in external systems without replicating the data into SAP HANA.

External systems are connected as remote sources, and their objects can be represented inside SAP HANA as virtual tables.
From an application perspective, these objects can be queried using standard SQL statements, while the data remains in the source system and is accessed during statement execution.

Official SAP HANA Smart Data Access documentation:
Data Access in the SAP HANA Cloud, SAP HANA Database

This article explains general processing behavior and supports correct interpretation during troubleshooting.
It does not provide configuration or performance tuning guidance.

Remote Sources and Virtual Tables
With SDA, SAP HANA integrates remote data access into SQL processing.
When a query references a virtual table, SAP HANA processes the statement, and data access is performed via the connected remote source during execution.
This behavior is part of the documented SAP HANA Smart Data Access architecture.

Query Processing Context
In SAP HANA Smart Data Access, SQL statements referencing virtual tables may involve both local SAP HANA processing and operations executed against the connected remote source.
As part of query processing, operations may be executed locally in SAP HANA or against the connected remote source.
Query execution may therefore include processing steps across system boundaries as part of normal system behavior.

Support-Relevant Distinction
From a support perspective, the following distinction is essential:
A statement can be initiated and processed by SAP HANA, while parts of the effective data processing may take place outside SAP HANA via the remote source and the communication layer.
Because of this execution boundary, the status of SAP HANA services alone does not describe the complete processing path when Smart Data Access is used.

Observations in Troubleshooting
During troubleshooting, it is possible that local SAP HANA processing appears normal while statements accessing virtual tables show different response times.

This can occur because the execution path may include:

the SAP HANA database
the network communication layer
the connected remote source

The overall response time therefore reflects the complete end-to-end processing path.

Documented SDA Scenarios
SAP documentation and SAP Notes describe different SDA-related scenarios that can influence behavior during execution.

SDA FAQ:
https://me.sap.com/notes/2180119

Examples include:

These scenarios may occur while the SAP HANA database itself remains available.

Interpreting Monitoring
When remote sources are involved, troubleshooting should consider the full end-to-end data access path rather than only local database activity.

Support Scope Clarification
When analyzing statements accessing virtual tables, the involved components may include:

SAP HANA database
network communication
remote data source

Observed behavior alone is not sufficient to determine a root cause and requires end-to-end analysis across all involved components.

Conclusion
SAP HANA Smart Data Access allows access to external data without replication.
Virtual tables represent remote objects, and data access from the connected system is part of normal execution behavior.
Statements executed in SAP HANA may therefore include processing steps outside the SAP HANA database, while SAP HANA operates according to its documented architecture.
Understanding this behavior supports correct interpretation during troubleshooting.

Disclaimer
This article summarizes documented system behavior based on publicly available SAP documentation and SAP Knowledge Base Articles.

Only official SAP documentation and SAP Notes are authoritative.

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