: Any form of indexing would always "replace" a document and never update it.
At a very low level this is true, but Solr does support "Atomic Updates" (aka "Partial Updates") that can be used to allow a lcient to only specify the values of an existing document they want to chagne and Solr will handle everything on the server side. : But i still dont get one thing, if i have two indexes that i try to merge : and both the indexes have some documents with same unique ids, they dont : overwrite each other. Instead what i have is two documents with same unique : id. Why does this happen? Anyone any clues? This seems like a completley unrelated question -- please start a new thread and provide full details of your situation and question in ordre for people to try to assist you... https://people.apache.org/~hossman/#threadhijack Thread Hijacking on Mailing Lists When starting a new discussion on a mailing list, please do not reply to an existing message, instead start a fresh email. Even if you change the subject line of your email, other mail headers still track which thread you replied to and your question is "hidden" in that thread and gets less attention. It makes following discussions in the mailing list archives particularly difficult. -Hoss