Hi Shawn, Please correct me If I'm wrong here, but don't the all inclusive range query [* TO *] and an only wildcard query like the one above essentially do the same thing from a black box perspective? In such a case wouldn't it be better to default an only wildcard query to an all inclusive range query?
On Wed, 17 Feb 2016, 06:47 Shawn Heisey <apa...@elyograg.org> wrote: > On 2/15/2016 9:22 AM, Jack Krupansky wrote: > > I should also have noted that your full query: > > > > (-persons:*)AND(-places:*)AND(-orgs:*) > > > > can be written as: > > > > -persons:* -places:* -orgs:* > > > > Which may work as is, or can also be written as: > > > > *:* -persons:* -places:* -orgs:* > > Salman, > > One fact of Lucene operation is that purely negative queries do not > work. A negative query clause is like a subtraction. If you make a > query that only says "subtract these values", then you aren't going to > get anything, because you did not start with anything. > > Adding the "*:*" clause at the beginning of the query says "start with > everything." > > You might ask why a query of -field:value works, when I just said that > it *won't* work. This is because Solr has detected the problem and > fixed it. When the query is very simple (a single negated clause), Solr > is able to detect the unworkable situation and implicitly add the "*:*" > starting point, producing the expected results. With more complex > queries, like the one you are trying, this detection fails, and the > query is executed as-is. > > Jack is an awesome member of this community. I do not want to disparage > him at all when I tell you that the rewritten query he provided will > work, but is not optimal. It can be optimized as the following: > > *:* -persons:[* TO *] -places:[* TO *] -orgs:[* TO *] > > A query clause of the format "field:*" is a wildcard query. Behind the > scenes, Solr will interpret this as "all possible values for field" -- > which sounds like it would be exactly what you're looking for, except > that if there are ten million possible values in the field you're > searching, the constructed Lucene query will quite literally include all > ten million values. Wildcard queries tend to use a lot of memory and > run slowly. > > The [* TO *] syntax is an all-inclusive range query, which will usually > be much faster than a wildcard query. > > Thanks, > Shawn > > -- Regards, Binoy Dalal
