> In __rec_review we're only forcing the split if the memory footprint is at least 2x the maxmempage, in __wt_page_in_func we're forcing the split if the memory footprint is at least 1x the maxmempage. Why are the two tests different, and why do we need 100 new leaf pages in one case, but 50 new leaf pages is sufficient in the other?

The idea here was that evicting the page is better than splitting and then evicting. So.. when the page gets to be larger than maxmempage, we start attempting to evict it via __wt_page_in_func. If we haven't managed to evict the page by the time it's grown to be twice the configured maximum, we split in memory.

I'm happy to talk through the pros/cons of splitting immediately vs giving eviction more chance of succeeding.