I've been looking around a lot to see how to use MongoDB in combination with Solr, and some questions here have partial responses, but nothing really concrete (more like theories). In my application, I will have lots and lots of documents stored in MongoDB (maybe up to few hundred millions), and I want to implement full-text searches on some properties of those documents, so I guess Solr is the best way to do this.

What I want to know is how should I configure/execute everything so that it has good performances? right now, here's what I do (and I know its not optimal):

1- When inserting an object in MongoDB, I then add it to Solr

```
SolrServer server = getServer();
SolrInputDocument document = new SolrInputDocument();
document.addField("id", documentId);
...
server.add(document);
server.commit();

```

2- When updating a property of the object, since Solr cannot update just one field, first I retrieve the object from MongoDB then I update the Solr index with all properties from object and new ones and do something like

```
StreamingUpdateSolrServer update = new StreamingUpdateSolrServer(url, 1, 0);
SolrInputDocument document = new SolrInputDocument();
document.addField("id", documentId);
...
update.add(document);
update.commit();

```

3- When querying, first I query Solr and then when retrieving the list of documents `SolrDocumentList` I go through each document and:

1. get the id of the document
2. get the object from MongoDB having the same id to be able to retrieve the properties from there

4- When deleting, well I haven't done that part yet and not really sure how to do it in Java

So anybody has suggestions on how to do this in more efficient ways for each of the scenarios described here? like the process to do it in a way that it won't take 1hour to rebuild the index when having a lot of documents in Solr and adding one document at a time? my requirements here are that users may want to add one document at a time, many times and I'd like them to be able to retrieve it right after