MULTIPLE INDEX BASED INFORMATION RETRIEVAL SYSTEM

• US 20100030773A1
• Filed: 07/20/2009
• Published: 02/04/2010
• Est. Priority Date: 07/26/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Patterson, Anna L.
• Granted Patent: US 8,560,550 B2
• Time in Patent Office: Days
• US Class Current: N/A
• CPC Class Codes: G06F 16/2228 Indexing structures
• CPC Class Codes: G06F 16/24578 using ranking
• CPC Class Codes: G06F 16/313 Selection or weighting of terms for indexing
• CPC Class Codes: G06F 16/93 Document management systems
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: G06F 16/9538 Presentation of query results
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99935 Query augmenting and refining, e.g. inexact access

Abstract

An information retrieval system uses phrases to index, retrieve, organize and describe documents. Phrases are identified that predict the presence of other phrases in documents. Documents are the indexed according to their included phrases. The document index is partitioned into multiple indexes, including a primary index and a secondary index. The primary index stores phrase posting lists with relevance rank ordered documents. The secondary index stores excess documents from the posting lists in document order.

Claims

1-12. -12. (canceled)

13. A method of providing an information retrieval system, the method comprising:

storing a primary index including primary phrase posting lists, each posting list associated with a phrase and including up to a maximum number of documents that contain the phrase, the documents rank ordered by respective relevance scores;

storing a secondary index including secondary phrase posting lists, each posting list associated with a primary phrase posting list in the primary index, and including documents that contain the phrase and which have relevance scores less than the relevance score of a lowest ranked document in the primary posting list for the phrase, the documents ordered by document identifier;

receiving a search query comprising at least one phrase;

responsive to the search query containing a first phrase having a primary posting list and a secondary posting list and a second phrase having only a primary posting list, intersecting, by operation of a processor adapted to manipulate data within a computer system, the primary posting list of the first phrase with the primary posting list of the second phrase to obtain a first set of common documents, and intersecting the secondary posting list of the first phrase with the primary posting list of the second phrase to obtain a second set of common documents, and conjoining the first and second sets of common documents; and

ranking the common documents.

14. An information retrieval system, comprising:

a primary index server system comprising a primary index, the primary index including primary phrase posting lists, each primary phrase posting list associated with a phrase and including up to a maximum number of documents that contain the phrase, the documents stored relative to one another in the primary index in rank order by respective relevance scores; and

a secondary index server system comprising a secondary index, the secondary index including secondary phrase posting lists, each secondary phrase posting list associated with a primary phrase posting list in the primary index, and including documents that contain the phrase and which have relevance scores less than the relevance score of a lowest ranked document in the primary posting list for the phrase, the documents stored relative to one another in the secondary index in order by respective document identifiers.

15. The system of claim 14, wherein the primary index stores, for each document, relevance attributes of the document.

16. The system of claim 14, wherein the secondary index stores substantially only document identification information.

17. The system of claim 14, wherein each primary phrase posting list in the primary index includes a first section wherein each document listed in the first section includes a first plurality of relevance attributes, and a second section wherein each document listed in the second section comprises a second plurality of relevance attributes that are subset of the first set of relevance attributes, and wherein the documents listed in the first section are ranked higher than the documents listed in the second section.