I am using Search API to define search pages and facets and I connect to a Solr engine. My search has been working perfectly until recently, after my last documents have been indexed. Now, every so often, two of my full-text fields on the "Fields" tab of the index configuration page just become unselected. Both fields are long text. This happens at least once a day. I then get no search results back and I have to go to the index's field selection tab (
admin/config/search/search_api/index/my_search/fields), select them again, and click "Save". The search results are then available immediately (i.e. it doesn't have to re-index first).
What is also worrying (actually more worrying), is that sometimes when this happens, the fields aren't even available to be selected AT ALL! When this happens, I have to clean the index completely using drush and then they become available again. Then I have to re-index all of my documents (about 8 million), which takes a whole day.
This site is live, so I am desperate. Please help!