Patent Document ID: 9361331
Application ID: 13801108

Base Claim:
1. A computer implemented method of indexing documents of a document collection, wherein each indexed document has a document identifier, the method comprising: storing a posting list of identifiers of documents of the document collection that contain a phrase; partitioning the posting list, by operation of at least one processor, into at least a first portion including identifiers of higher ranked documents and a second portion including identifiers of lesser ranked documents, the partitioning being based on a relevance score for a document identified in the posting list indicating the document's relevance to the phrase; storing the first portion in a primary index; and storing the second portion in a secondary index.

---

Claim 2:
2. The method of claim 1 , wherein the identifiers of the lesser ranked documents of the second portion being stored relative to one another in the secondary index in numerical order of the respective document identifiers of the ranked documents.