Hi,
In the meantime I programatically increased the timeout for getting the statistics. It should take about 40 seconds to load, but everything seems to be all right: https://i.imgur.com/5K8qUZ2.png
The indexing was correct, only the number of rows was taking very long time to fetch. The statistics can be 5% off of the real rows number, it is only an approximation, as MySQL is not able to correctly count rows via a specific table command. If it sometimes returns 0, you can safely ignore that.
1. The content means the post/product content field.
2. The length is the each keyword length that is found for indexing. Ex. “and” has a length of 3, thus if you have this value set to 4, then this word is not indexed.
Your current configuration seems perfect to me – there are over 2.5M keywords, for 41K posts, that is more than plenty per product.