Oh, thanks for the pointer! I'll look to see if I can use that.
On Wed, Jul 3, 2013 at 1:53 PM, Jack Krupansky <j...@basetechnology.com>wrote: > There is a Lucene filter that you can use to check efficiently for whether > a field has a value or not. > > new ConstantScoreQuery(new FieldValueFilter(String field, boolean negate)) > > -- Jack Krupansky > > -----Original Message----- From: David Carlton > Sent: Wednesday, July 03, 2013 4:27 PM > To: java-user@lucene.apache.org > Subject: handling nonexistent fields in an index > > > I have a bunch of Lucene indices lying around, and I want to start adding a > new field to documents in new indices that I'm generating. So, for a given > index, either every document in the index will have that field or no > document will have that field. > > The new field has a default value; and I would like to write a query that, > when applied to old indices, matches all documents, while when applied to > new indices, it will only match documents with that specific default value. > (Probably the query will include other restrictions, but the other > restrictions have nothing to do with the new field, so they'll apply to > both indices.) > > > I can, of course, write two different queries, one for the old indices and > one for the new indices; for layering reasons, I'd prefer not to do that, > but it's a possibility. (I can't, however, go back to the old indices and > add the new field in.) > > Any suggestions for how to write a single query that will work in both > places? Basically, what I want is a query that says something like > > (field IS MISSING) OR (field = DEFAULT_VALUE) > > If it matters, the new field will only take one of a small number of > values, ten or so. > > > The one hint I've turned up when googling is this: > http://stackoverflow.com/**questions/4365369/solr-search-** > for-documents-where-a-field-**doesnt-exist<http://stackoverflow.com/questions/4365369/solr-search-for-documents-where-a-field-doesnt-exist> > > It talks in terms of Solr, but hopefully I can figure out how to translate > that into stock Lucene? Thinking out loud about what it suggests, I guess > maybe I can generate a WildcardQuery for my field with * (which I hope > won't be too expensive, given how few values my field has), and then do > something like > > (field = DEFAULT_VALUE) OR NOT (field matches *) > > And then I have to translate that into Lucene BooleanQuery syntax; I think > I can probably handle that step of things (I've done that sort of thing > before), but if anybody has tips, I'm all ears. > > > Basically, any suggestions would be welcome, whether about the basic > approach or about the details. And I would in particular very much > appreciate advice as to whether or not WildcardQuery(field, *) will have > good performance if field only takes a small number of values. > > -- > David Carlton > carl...@sumologic.com > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > java-user-unsubscribe@lucene.**apache.org<java-user-unsubscr...@lucene.apache.org> > For additional commands, e-mail: > java-user-help@lucene.apache.**org<java-user-h...@lucene.apache.org> > > -- David Carlton carl...@sumologic.com
