Nalini, Right now the best you can do is to use <copyField> to combine everything into a catch-all for spellchecking purposes. While this seems wasteful, this often has to be done anyhow because typically you'll need less/different analysis for spellchecking than for searching. But rather than having separate <copyField>s to create multiple dictionaries, put everything into one field to create a single "master" dictionary.
>From there, you need to set "spellcheck.collate" to true and also >"spellcheck.maxCollationTries" greater than zero (5-10 usually works). The >first parameter tells it to generate re-written queries with spelling >suggestions (collations). The second parameter tells it to weed out any >collations that won't generate hits if you re-query them. This is important >because having unrelated keywords in your master dictionary will increase the >chances the spellchecker will pick the wrong words as corrections. There is a significant caveat to this: The spellchecker typically only suggests for words in the dictionary. So by creating a huge, master dictionary you might find that many misspelled words won't generate suggestions. See this thread for some workarounds: http://lucene.472066.n3.nabble.com/Improving-Solr-Spell-Checker-Results-td3658411.html I think having multiple, per-field dictionaries as you suggest might be a good way to go. While this is not supported, I don't think its because of performance concerns. (There would be an overhead cost to this but I think it would still be practical). It just hasn't been implemented yet. But we might be getting to a possible start to this type of functionality. In https://issues.apache.org/jira/browse/SOLR-2585 a separate spellchecker is added that just corrects wordbreak (or is it "word break"?) problems, then a "ConjunctionSolrSpellChecker" combines the results from the main spellchecker and the wordbreak spellcheker. I could see a next step beyond this being to support per-field dictionaries, checking them separately, then combining the results. James Dyer E-Commerce Systems Ingram Content Group (615) 213-4311 -----Original Message----- From: Nalini Kartha [mailto:nalinikar...@gmail.com] Sent: Wednesday, January 25, 2012 11:56 AM To: solr-user@lucene.apache.org Subject: Using multiple DirectSolrSpellcheckers for a query Hi, We are trying to use the DirectSolrSpellChecker to get corrections for mis-spelled query terms directly from fields in the Solr index. However, we need to use multiple fields for spellchecking a query. It looks looks like you can only use one spellchecker for a request and so the workaround for this it to create a copy field from the fields required for spell correction? We'd like to avoid this because we allow users to perform different kinds of queries on different sets of fields and so to provide meaningful corrections we'd have to create multiple copy fields - one for each query type. Is there any reason why Solr doesn't support using multiple spellcheckers for a query? Is it because of performance overhead? Thanks, Nalini
