Java: Config for SAP HANA HEX Engine (#526)

* Update persistence-services.md Document config for SAP HANA HEX Engine * Update java/persistence-services.md * Apply suggestions from code review Co-authored-by: Matthias Schur <[email protected]> * Update java/persistence-services.md --------- Co-authored-by: René Jeglinsky <[email protected]> Co-authored-by: Matthias Schur <[email protected]>
cap-js · Nov 14, 2023 · acef96a · acef96a
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diff --git a/java/persistence-services.md b/java/persistence-services.md
@@ -121,10 +121,25 @@ cds:
 
 ### SAP HANA
 
+#### Service Bindings
+
 SAP HANA can be configured when running locally as well as when running productively in the cloud. The datasource is auto-configured based on available service bindings in the `VCAP_SERVICES` environment variable or locally the _default-env.json_. This only works if an application profile is used, that doesn't explicitly configure a datasource using `spring.datasource.url`. Such an explicit configuration always takes precedence over service bindings from the environment.
 
 Service bindings of type *service-manager* and, in a Spring-based application, *hana* are used to auto-configure datasources. If multiple datasources are used by the application, you can select one auto-configured datasource to be used by the default Persistence Service through the property `cds.dataSource.binding`.
 
+#### SQL Optimization Mode
+
+By default, the SAP HANA adapter in CAP Java generates SQL that is compatible with SAP HANA 2.x ([HANA Service](https://help.sap.com/docs/HANA_SERVICE_CF/6a504812672d48ba865f4f4b268a881e/08c6e596b53843ad97ae68c2d2c237bc.html)) and [SAP HANA Cloud](https://www.sap.com/products/technology-platform/hana.html).
+To generate SQL that is optimized for the new [HEX engine](https://help.sap.com/docs/SAP_HANA_PLATFORM/9de0171a6027400bb3b9bee385222eff/3861d0908ef14e8bbec1d76ea871ac0f.html#sap-hana-execution-engine-(hex)) in SAP HANA Cloud, set the [CDS property](development/properties#cds-properties):
+
+```yaml
+cds.sql.hana.optimizationMode: hex
+```
+
+:::tip
+Use the [hints](../java/query-execution#hana-hints) `hdb.USE_HEX_PLAN` and `hdb.NO_USE_HEX_PLAN` to overrule the configured optimization mode per statement.
+:::
+
 ### PostgreSQL { #postgresql-1 }
 
 PostgreSQL can be configured when running locally as well as when running productively in the cloud. Similar to HANA, the datasource is auto-configured based on available service bindings, if the feature `cds-feature-postgresql` is added.