fts error recovery

When a message is received, that is supposed to be added to the fts index, and an fts error occurs (like the Solr server is offline for some reason) - Dovecot logs that error and stores the message. Later, the fts system is available and new messages are added to the fts index without issue.

Will the "missed" messages get added? Or would this require a manual re-indexing?

-- Daniel