This functionality was removed in SDx Update 32. From SDx Update 32, abstract relationship definitions are no longer supported in the OData metadata. As you cannot define the navigation to expose object types in OData metadata using abstract RelDefs, the generation of the OData model has no performance impact on the log on process.
The following applies before Update 32.
Previously, if the system exposed objects in OData metadata using abstract relationship definitions (ReldDefs), the generation of the OData model takes too long, so users were unable to log on to Web Client after upgrading from IM 2018R1 to 2019 (SPF and SDx). Navigation defined using abstract RelDefs causes a significant performance impact on the generation of the OData model as a significant number of objects have to be exposed. This affects logging onto the Web Client.
For more information, see Unable to log on to Web Client after upgrade.