optimize storage of performance data

[woolfg]

the two tables with performance data of episodes are quite big. around 8GB just for the few podcasts we store at the moment....

• spotify changes data int he first 14 days only, after that it stays the same. this would also simplify the crawler if we do not fetch the old data at all?
• we could reduce the storage a lot
• also apple might be similar after some time? maybe we can just store if the entry has changed?
• the storage should be easy as we store a changed value only. we would have to extend the date to a start and end date. the latest value would be the empty end date row?

[mre]

Great idea. I like it. 💡