Rewriting queries - a discussion based on the Querqy framework

In many search applications, query rewriting seems to be a forgotten or only loosely defined concept. Often, it is implemented late in the development process in order to overcome specific search relevance issues. This means that the implications of integrating several query rewriting components (e.g. synonyms and boosting queries), their impact on ranking functions, such as BM25, and their interaction with field weights are often unclear and sometimes surprising.

My talk provides an argument for using a well-defined query rewriting component. I shall discuss approaches to modelling and transforming the query and examine problems in matching and ranking that occur when rewritten queries are mapped to fields. I will then offer possible solutions to these problems, using the Querqy query rewriting framework, which is available as an open source library for Solr and Elasticsearch.

René Kriegler

René has been working as a freelance search consultant for clients in Germany and abroad for more than ten years, often contracting for OpenSource Connections. Although he is interested in all aspects of search and NLP, key areas include search relevance consulting and e-commerce search. His technological focus is on Solr/Elasticsearch/Lucene. René co-organises MICES (Mix-Camp E-Commerce Search, Berlin, 10 June). He maintains the Querqy open source library.