How to avoid dropping existing index when reindexing

Question

When reindexing Sunspot, the existing index is cleared/dropped first. This means user will see blank search results for a short time, which is bad for production environment. Is there a way to do reindexing without clearing existing indexes?

The clearing occurs when I call rake task, and when I call solr_reindex in console.

Answer 1

By looking into the code, I think doing a Model.solr_index is enough. When indexing is complete, one can start searching into new indexed fields.

The searchable schema is not something shared across all records from one model. Therefore indexing a single record will update the searchable schema of that record.