is there a way to determine whether Trackster is the cause?
The only place where Trackster caches data is in the SummaryTreeDataProvider. In galaxy-central, the relevant line is 709 in lib/galaxy/visualization/genome/data_providers.py :
-- CACHE = LRUCache( 20 ) # Store 20 recently accessed indices for performance --
Try setting the cache size low or to 0 and see if that addresses the memory issue.
Best, J.