[lobster_johnson]

I think treating Solr/ES as a primary data store would be a horrible idea. But the problem is equally annoying if you're using it as an expendable search index.

There is no technical reason why Solr/ES could not do diff-based indexing. ES (I don't know about Solr) admittedly uses a single Lucene index per logical index, so changing a single field mapping involves reindexing the whole index, not just that one mapping.

But if the mappings were properly versioned ES could simply create a new version, index everything (from the original contents), and then swap. Locking the original index should be a non-issue.