Set cache expiration timeout explicitly (instead of depending on the 5 minute default)
The cache mechanism for dataproduct fields used the (incorrectly assumed to be infinite) timeout. The default timeout is actually 5 minutes, so that after 5 minutes pages become slow again in LDVSpec. This time, set the cache expiration timeout explicity.
Then, in the future (e.g., in scope of the LTA Datascraper), add a way to flush/invalidate cache keys.