What is "Pages created in the cache"?

Question

Looking at these two DBs in my environment:
Pool File: x.db
8192    Page size
0       Requested pages mapped into the process' address space
78M     Requested pages found in the cache (34%)
149M    Requested pages not found in the cache (149056231)
884390  Pages created in the cache
149M    Pages read into the cache (149049683)
11M     Pages written from the cache to the backing file (11213750)
Pool File: y.db
4096    Page size
0       Requested pages mapped into the process' address space
626M    Requested pages found in the cache (77%)
181M    Requested pages not found in the cache (181920907)
2013    Pages created in the cache
181M    Pages read into the cache (181778435)
75M     Pages written from the cache to the backing file (75856843) Yes, the cache size needs to be increased. But customers tend to be less than satisfied with answers like "keep increasing it until the hit rate levels off."
I think I understand "found" and "not found" and "read into", but what does "Pages created in the cache" mean?
What can we conclude from the first one having 149M pages not found in cache, and 884K pages created,
while the second one has 181M pages not found in cache, but only 2K pages created??

Answer 1

Can we determine how many unique pages are involved? How many of those "Pages read into the cache" are the same pages being read multiple times because they were flushed out in between? As compared to pages read into the cache, and then only used once?