Elasticsearch

elasticsearch

elasticsearch.org Open Source Distributed Real Time Search & Analytics

elasticsearch - http://www.elasticsearch.org/

Install

Elastic Search:

rpm --import http://packages.elasticsearch.org/GPG-KEY-elasticsearch

cat > /etc/yum.repos.d/elastic.repo << "EOF"
[elasticsearch-1.1]
name=Elasticsearch repository for 1.1.x packages
baseurl=http://packages.elasticsearch.org/elasticsearch/1.1/centos
gpgcheck=1
gpgkey=http://packages.elasticsearch.org/GPG-KEY-elasticsearch
enabled=1
EOF

yum install elasticsearch

# start on boot
sudo /sbin/chkconfig --add elasticsearch

# start manually
sudo service elasticsearch start

# see if it runs
curl -XGET 'http://localhost:9200'

# Create Stage Index:
curl -XPUT 'http://localhost:9200/somestage'

Paths:

Data location: /var/lib/elasticsearch
Config: /etc/sysconfig/elasticearch
Exe: /usr/share/elasticsearch
Startup: /etc/init.d/elasticsearch
Config: /etc/elasticsearch/*.yml

Search:

curl -XGET 'http://localhost:9200/_search'

Configuration

• ES_HEAP_SIZE environment variable allows to set the heap memory that will be allocated to elasticsearch java process. It will allocate the same value to both min and max values.

curl localhost:9200/_nodes/process?pretty

config/elasticsearch.yml:

bootstrap.mlockall: true

References:

• Configuration - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/setup-configuration.html
• ElasticSearch and Logstash Tuning – jablonskis - http://jablonskis.org/2013/elasticsearch-and-logstash-tuning/index.html

CRUD

Create

curl -XPUT "http://localhost:9200/movies/movie/1" -d'
{
    "title": "title1",
    "director": "director1",
    "year": 100
}'

{"_index":"movies","_type":"movie","_id":"1","_version":1,"created":true}

Read

curl -XGET "http://localhost:9200/movies/movie/1"

Update

Same as create, but return json will have:

{"_index":"movies","_type":"movie","_id":"1","_version":2,"created":false}

Delete

curl -XDELETE "http://localhost:9200/movies/movie/1"

Search

http://localhost:9200/_search - Search across all indexes and all types.
http://localhost:9200/movies/_search - Search across all types in the movies index.
http://localhost:9200/movies/movie/_search - Search explicitly for documents of type movie within the movies index.

Basic free text search

search for the word "kill"

curl -XPOST "http://localhost:9200/_search" -d'
{
    "query": {
        "query_string": {
            "query": "kill"
        }
    }
}'

Search only in titles:

curl -XPOST "http://localhost:9200/_search" -d'
{
    "query": {
        "query_string": {
            "query": "ford",
            "fields": ["title"]
        }
    }
}'

Filter

Query with filter:

curl -XPOST "http://localhost:9200/_search" -d'
{
    "query": {
        "filtered": {
            "query": {
                "query_string": {
                    "query": "drama"
                }
            },
            "filter": {
                "term": { "year": 1962 }
            }
        }
    }
}'

Just filter:

curl -XPOST "http://localhost:9200/_search" -d'
{
    "query": {
        "filtered": {
            "query": {
                "match_all": {
                }
            },
            "filter": {
                "term": { "year": 1962 }
            }
        }
    }
}'

curl -XPOST "http://localhost:9200/_search" -d'
{
    "query": {
        "constant_score": {
            "filter": {
                "term": { "year": 1962 }
            }
        }
    }
}'

Index

In order to index a first JSON object we make a PUT request to the REST API to a URL made up of the index name, type name and ID. That is:

http://localhost:9200/<index>/<type>/[<id>]

Tutorials

ElasticSearch 101 - A getting started tutorial - http://joelabrahamsson.com/elasticsearch-101/