SAP HANA Query Execution Engine

SAP HANA Query Execution Engine

1. HEX engine

The SAP HANA Execution Engine (HEX) is a new engine that combines the functionality of other engines, such as the join engine and OLAP engine. Queries that are not supported by HEX or where an execution is not considered beneficial are automatically routed to the former engine.

2. ESX engine

The SAP HANA Extended SQL Executor (ESX) is a new frontend execution engine that replaces the row engine in part, but not completely. It retrieves database requests at session level and delegates them to lower-level engines like the join engine and calculation engine.

3. Join engine

The join engine is used to run plain SQL. Column tables are processed in the join engine.

4. OLAP engine

The OLAP engine is primarily used to process aggregate operations. Calculated measures (unlike calculated columns) are processed in the OLAP engine.

5. Calculation engine

Calculation views, including star joins, are processed by the calculation engine. To do so, the calculation engine may call any of the other engines directly or indirectly.

6. Row engine

The row engine is designed for OLTP scenarios. Some functionality, such as particular date conversions or window functions, are only supported in the row engine. The row engine is also used when plain SQL and calculation engine functions are mixed in a calculation view.

7. MDS engine

SAP HANA multi-dimensional services (MDS) is used to process multidimensional queries including aggregation, transformation, and calculation.

The queries are translated into an SAP HANA calculation engine execution plan or SQL, which is executed by the SAP HANA core engines.

MDS is integrated with the SAP HANA Enterprise Performance Management (EPM) platform and is used by reporting and planning applications.

The query languages currently supported use the Information Access (InA) model. The InA model simplifies the definition of queries with rich or even complex semantics. Data can be read from all kinds of SAP HANA views, EPM plan data containers, and so on. The InA model also includes spatial (GIS) and search features.