What does "boost" mean for documents and queries?

Question

I'm pretty new to Lucene, and I'm trying to understand more about boosting documents and queries. I'm finding a lot of documents about how to configure the boost of a document, but what does this mean?

All I can really find now is that it affects the scoring, but it's not even clear to me whether or not a higher or lower value will result in a better "score" when doing the search. I've searched the Google and the Lucene wiki and really haven't found any generic explanation of what this actually is...

Any help would be greatly appreciated!

Answer 1

In Lucene, you can boost a document or a field. In the document case, all of its fields will be boosted with the value you use to boost the document.

By default, all documents have no boost or rather they all have the same boost factor of 1.0. By changing it, Lucene will consider it more or less important. For example: Boost 1.5 is greater, which means more important.

You can do boosting both when you index your document or when you create a query.