solr search for documents where a field doesn’t exist
-field:[* TO *] In SolrNet, use a negated SolrHasValueQuery
lucene
How can I search on a list of values using Solr/Lucene?
Use field:(value1 value2 value3) or if your default operator is AND then use field:(value1 OR value2 OR value3)
Solr/Solrj: How can I determine the total number of documents in an index?
Here’s what I’m using. Is this canonical? Is there a better way? SolrQuery q = new SolrQuery(“*:*”); q.setRows(0); // don’t actually request any data return server.query(q).getResults().getNumFound();
Lucene indexing: Store and indexing modes explained
Store.Yes Means that the value of the field will be stored in the index Store.No Means that the value of the field will NOT be stored in the index Store.Yes/No does not affect the indexing or searching with lucene. It just tells lucene if you want it to act as a datastore for the values … Read more
What are segments in Lucene?
The Lucene index is split into smaller chunks called segments. Each segment is its own index. Lucene searches all of them in sequence. A new segment is created when a new writer is opened and when a writer commits or is closed. The advantages of using this system are that you never have to modify … Read more
Elasticsearch always returning “mapping type is missing”
Turns out this is happening because the mapping needs to be applied to the type: I tried applying it to the wrong thing: curl -XPUT 10.160.86.134:9200/products/_mapping -d ‘{ It needs to be applied to the type like so: curl -XPUT 10.160.86.134:9200/products/product/_mapping -d ‘{ It’s sad that a simple google search couldn’t answer this. Also the … Read more
Retrieving specific fields in a Solr query?
/?q=query&fl=field1,field2,field3
Why are document stores like Lucene / Solr not included in NoSQL conversations?
I once listened to an interview with author Ursula K. LeGuin about fiction writing. The interviewer asked her about authors who work in different genre of writing. What makes one author a romance writer, and another a mystery writer, and another a science fiction writer? LeGuin responded by explaining: Genre is about marketing, not about … Read more
How does Lucene work
Lucene is an inverted full-text index. This means that it takes all the documents, splits them into words, and then builds an index for each word. Since the index is an exact string-match, unordered, it can be extremely fast. Hypothetically, an SQL unordered index on a varchar field could be just as fast, and in … Read more