Monday, November 01, 2010

CouchDB and Lucene

Quick notes to self on fulltext search and CouchDB. Note that links to CouchDB are local to my machine(s),and won't work unless you are me, or have a copy of the same database running on your machine). CouchDB and Lucene adds fulltext indexing to CouchDB. After a few false starts I now have this working. The documentation is a little misleading, you don't need to clone the github repository, nor use Maven to build couchdb-lucene (at least, I didn't). Instead I grabbed couchdb-lucene-0.5.6, unpacked it, used that as is.

To configure CouchDB I ended up editing the configuration using Futon (there's a link "Add a new section" down the bottom of the Configuration page), then I restarted CouchDB. The things to add are:

os_process_timeout=60000 ; increase the timeout from 5 seconds.
fti=/path/to/python /path/to/couchdb-lucene/tools/
_fti = {couch_httpd_external, handle_external_req, <<"fti">>}

To start couchdb-lucene, just cd couchdb-lucene-0.5.6 and bin/run.

Then it's a case of adding a fulltext index. In Futon I start adding a regular design document, then edit the Javascript. For example, here is a simple index on document titles:

"_id": "_design/lucene",
"_rev": "2-96b333dfc77866a13c0de7f856d27b6c",
"language": "javascript",
"fulltext": {
"by_title": {
"index": "function(doc) {
var ret=new Document();
return ret;

Once the indexing has been completed, you can search the CouchDB database using a URL like this: http://localhost:5984/col2010ref/_fti/_design/lucene/by_title?q=frog+new+species.

Lots more to do here, but with spatial queries and now fulltext search, it's time to start building something...