ElasticSearch autocomplete returning 0 hits - mongodb

Question

I am trying to build an autocomplete feature for our database running on MongoDB. We need to provide autocomplete which lets users complete their queries by offering suggestions while they are typing in the search box.
I have a collection of articles from various sources, which is having the following fields :
{
"title" : "Its the title of a random article",
"cont" : { "paragraphs" : [ .... ] },
and so on..
}
I went through a video by Clinton Gormley. From 37:00 through 42:00 minute, Gormley describes an autocomplete using edgeNGram. Also, I referred to this question to recognize that both are almost the same things, just the mappings differ.
So based on these experiences, I built almost identical settings and mapping and then restored articles collection to ensure that it is indexed by ElasticSearch
The indexing scheme is as follows:
POST /title_autocomplete/title
{
"settings": {
"analysis": {
"filter": {
"autocomplete": {
"type": "edgeNGram",
"min_gram": 2,
"max_gram": 50
}
},
"analyzer": {
"title" : {
"type" : "standard",
"stopwords":[]
},
"autocomplete": {
"type" : "autocomplete",
"tokenizer": "standard",
"filter": ["lowercase", "autocomplete"]
}
}
}
},
"mappings": {
"title": {
"type": "multi_field",
"fields" : {
"title" : {
"type": "string",
"analyzer": "title"
},
"autocomplete" : {
"type": "string",
"index_analyzer": "autocomplete",
"search_analyzer" : "title"
}
}
}
}
}
But when I run the search query, I am unable to get any hits!
GET /title_autocomplete/title/_search
{
"query": {
"bool" : {
"must" : {
"match" : {
"title.autocomplete" : "Its the titl"
}
},
"should" : {
"match" : {
"title" : "Its the titl"
}
}
}
}
}
Can anybody please explain what's wrong with the mapping query or settings? I have been reading ElasticSearch docs for over 7 days now but seem to get nowhere more than full text searches!
ElastiSearch version : 0.90.10
MongoDB version : v2.4.9
using _river
Ubuntu 12.04 64bit
UPDATE
I realised that mapping is screwed after applying previous settings:
GET /title_autocomplete/_mapping
{
"title_autocomplete": {
"title": {
"properties": {
"analysis": {
"properties": {
"analyzer": {
"properties": {
"autocomplete": {
"properties": {
"filter": {
"type": "string"
},
"tokenizer": {
"type": "string"
},
"type": {
"type": "string"
}
}
},
"title": {
"properties": {
"type": {
"type": "string"
}
}
}
}
},
"filter": {
"properties": {
"autocomplete": {
"properties": {
"max_gram": {
"type": "long"
},
"min_gram": {
"type": "long"
},
"type": {
"type": "string"
}
}
}
}
}
}
},
"content": {
... paras and all ...
}
"title": {
"type": "string"
},
"url": {
"type": "string"
}
}
}
}
}
Analyzers and filters are actually mapped into the document after the settings are applied whereas original title field is not affected at all! Is this normal??
I guess this explains why the query is not matching. There is no title.autocomplete field or title.title field at all.
So how should I proceed now?

Answer 1

For those facing this problem, its better to delete the index and start again instead of wasting time with the _river just as DrTech pointed out in the comment.
This saves time but is not a solution. (Therefore not marking it as answer.)

Answer 2

The key is to set up the mappings and index before you initiate the river.
We had an existing setup with a mongodb river and an index called coresearch that we wanted to add autocomplete capacity to, this is the set of commands we used to delete the existing index and river and start again.
Stack is:
ElasticSearch 1.1.1
MongoDB 2.4.9
ElasticSearchMapperAttachments v2.0.0
ElasticSearchRiverMongoDb/2.0.0
Ubuntu 12.04.2 LTS
curl -XDELETE "localhost:9200/_river/node"
curl -XDELETE "localhost:9200/coresearch"
curl -XPUT "localhost:9200/coresearch" -d '
{
"settings": {
"analysis": {
"filter": {
"autocomplete_filter": {
"type": "edge_ngram",
"min_gram": 1,
"max_gram": 20
}
},
"analyzer": {
"autocomplete": {
"type": "custom",
"tokenizer": "standard",
"filter": [
"lowercase",
"autocomplete_filter"
]
}
}
}
}
}'
curl -XPUT "localhost:9200/coresearch/_mapping/users" -d '{
"users": {
"properties": {
"firstname": {
"type": "string",
"search_analyzer": "standard",
"index_analyzer": "autocomplete"
},
"lastname": {
"type": "string",
"search_analyzer": "standard",
"index_analyzer": "autocomplete"
},
"username": {
"type": "string",
"search_analyzer": "standard",
"index_analyzer": "autocomplete"
},
"email": {
"type": "string",
"search_analyzer": "standard",
"index_analyzer": "autocomplete"
}
}
}
}'
curl -XPUT "localhost:9200/_river/node/_meta" -d '
{
"type": "mongodb",
"mongodb": {
"servers": [
{ "host": "127.0.0.1", "port": 27017 }
],
"options":{
"exclude_fields": ["time"]
},
"db": "users",
"gridfs": false,
"options": {
"import_all_collections": true
}
},
"index": {
"name": "coresearch",
"type": "documents"
}
}'