Reduce memory footprint in raw data importer
The memory footprint of the raw data importer can be up to several hundred megabytes when the raw bioassay is connected to an array design. The reason is that the features and reporters on the array design are pre-loaded (for performance reasons) and kept in memory.
It is however not necessary to keep all information in memory since we only need a few properties (eg. feature id, position and reporter id). These properties could be kept in a special object and which can then be used as a proxy object for the real
FeatureData object when inserting to the database.