Goal
Goal is to ensure that retainGlobalAlwaysOn is enabled on all partitions.
Why
The API variable api.retainGlobalin groovy logic was used to control behavior of api.global cache in calculation engine before api.local was introduced. If the api.retainGlobal was false, the api.global cache behaved like api.local that means was cleared between line items. This is unexpected behavior which typically causes a performance issue.
The default value of the api.retainGlobal variable is defined by Advanced configuration option retainGlobalAlwaysOn.
Since api.local was introduced, api.global cache is now expected to be kept between calculation of individual line items.
api.globalgets persisted on CF. But that is not a known feature and therefore not expected. Having big api.global cache can cause a performance issue. Currently the only way how to disable it is to set retainGlobal = false. But this will be possible once PFUN-34916 is implemented.
See also api.global versus api.local