Cache priority is a way to assign priority to cache locations (servers) based on IMPAX Client proximity. Using cache priority, sites can accommodate for slower network bandwidths between multiple facilities in a single database environment.
In IMPAX, the Application Server determines the best cache for the IMPAX Client using a service that includes find_best_cache location. Starting in IMPAX 6.3.1, station containers can assume a virtual AE title, allowing you to create an association between the various groups of Clients and each image server in the cluster.
That is, the virtual AE title allows the Application Server’s metadata service to find the most suitable Network Gateway (using find_best_cache_location logic) based on cache priority.
Cache priority on the IMPAX Client
The following are the key points to understand for setting up cache priority on the IMPAX Client:
Base the cache priority on the station container.
Group workstations in station containers representing the network proximity to the cache location.
Note:
Sites using the IMPAX RIS may define station containers to control how different Clients access RIS information (through the Services Access tab). Keep this in mind when creating station containers for cache priority.
Use a virtual AE title to represent the station container.
Represent each image server in the IMPAX cluster as a storage point in the enterprise.
For multiple Curators, only the master Curator is listed as a storage point (because there is only one web cache server).
The ae_ref associated with the virtual AE title is used by the metadata service for image_location requests.
The metadata service provides the find_best_cache_location logic during Client image retrieval.
Cache priority on the Administration Tools
The following are the key points to understand for setting up cache priority on the Administration Tools:
Configure cache priorities using the Image Access Manager.
In the Image Access Manager, assign priority by source and destination AE titles.
The Image Access Manager sets the priority and ae_refs in the Source and Destination columns of the OSR_AE_PRIORITY table.
The ae_refs are linked to AE_titles column in the map_ae table.