The Compressor Scheduler process schedules the lossy compression of studies in the cluster. Compressor Scheduler creates a Compress job for each study that fulfills defined conditions, including diagnostically read and older than a defined Read Study Age, or not diagnostically read and older than a defined Study Age.
When lossy archiving is disabled, a study must be fully archived before it
can be lossy JPEG compressed, unless the station name is configured in the Source
Manager to not archive studies from that station (for example, Telerad studies),
in which case, the dosr_study.archive_flag parameter must be <NULL>.
When lossy archiving is enabled, a study is lossy compressed in the cache before it is archived. However, if a study was lossless archived prior to enabling lossy archiving, it is lossy compressed only when it is retrieved to cache.
Any lossless copy retrieved from an archive is lossy compressed following the rules defined in the Compressor Scheduler. They are compressed immediately as the conditions are fulfilled and depending on the system configuration (for example, they are only compressed during the times that Compressor Scheduler is configured to run). However, if a user protects a study using the IMPAX Client or Study Manager (which sets the dosr_study_location.protected parameter to T), the study is not lossy compressed.
 | Note: Protected studies are not deleted by Autopilot; therefore, these studies must be manually unprotected or deleted from cache. |
The Compressor job is created on a specific Compressor queue, which is configured on a per-station basis. Each Compressor processes jobs in its queue. Use the Source Manager to specify the Compressor queue on a per-station basis. In a cluster with multiple cache servers, more than one compressor can be running.