1. A method comprising the steps of: obtaining a base query having a plurality of base query terms; accessing a plurality of problem log files; extracting words, contained in a corpus vocabulary, from said plurality of problem log files; based on said words extracted from said plurality of problem log files, generating a first expanded query from said base query; and querying said corpus, via a query engine and a corpus index, with a second expanded query related to said first expanded query; further comprising determining that at least one of said query terms is in said corpus vocabulary; wherein said generating comprises, responsive to said determining that at least one of said query terms is in said corpus vocabulary: picking one or more words having highest relevance to said query terms from among said words extracted in said extracting step, based on a topic model of said corpus; and adding at least one of said words having said highest relevance to said base query to generate said first expanded query.