9.22. Elasticsearch Connector#

Overview#

The Elasticsearch Connector allows access to Elasticsearch data from Presto. This document describes how to setup the Elasticsearch Connector to run SQL queries against Elasticsearch.

Note

Elasticsearch 6.0.0 or later is required.

Configuration#

To configure the Elasticsearch connector, create a catalog properties file etc/catalog/elasticsearch.properties with the following contents, replacing the properties as appropriate:

connector.name=elasticsearch
elasticsearch.host=localhost
elasticsearch.port=9200
elasticsearch.default-schema-name=default

Configuration Properties#

The following configuration properties are available:

Property Name Description
elasticsearch.host Host name of the Elasticsearch server.
elasticsearch.port Port of the Elasticsearch server.
elasticsearch.default-schema-name Default schema name for tables.
elasticsearch.scroll-size Maximum number of hits to be returned with each Elasticsearch scroll request.
elasticsearch.scroll-timeout Timeout for keeping the search context alive for scroll requests.
elasticsearch.request-timeout Timeout for Elasticsearch requests.
elasticsearch.connect-timeout Timeout for connections to Elasticsearch hosts.
elasticsearch.max-retry-time Maximum duration across all retry attempts for a single request.
elasticsearch.node-refresh-interval How often to refresh the list of available Elasticsearch nodes.

elasticsearch.host#

Specifies the hostname of the Elasticsearch node to connect to.

This property is required.

elasticsearch.port#

Specifies the port of the Elasticsearch node to connect to.

This property is optional; the default is 9200.

elasticsearch.default-schema-name#

Defines the schema that contains all tables defined without a qualifying schema name.

This property is optional; the default is default.

elasticsearch.scroll-size#

This property defines the maximum number of hits that can be returned with each Elasticsearch scroll request.

This property is optional; the default is 1000.

elasticsearch.scroll-timeout#

This property defines the amount of time (ms) Elasticsearch keeps the search context alive for scroll requests

This property is optional; the default is 1m.

elasticsearch.request-timeout#

This property defines the timeout value for all Elasticsearch requests.

This property is optional; the default is 10s.

elasticsearch.connect-timeout#

This property defines the timeout value for all Elasticsearch connection attempts.

This property is optional; the default is 1s.

elasticsearch.max-retry-time#

This property defines the maximum duration across all retry attempts for a single request to Elasticsearch.

This property is optional; the default is 20s.

elasticsearch.node-refresh-interval#

This property controls how often the list of available Elasticsearch nodes is refreshed.

This property is optional; the default is 1m.

TLS Security#

The Elasticsearch connector provides additional security options to support Elasticsearch clusters that have been configured to use TLS.

The connector supports key stores and trust stores in PEM or Java Key Store (JKS) format. The allowed configuration values are:

Property Name Description
elasticsearch.tls.enabled Whether TLS security is enabled.
elasticsearch.tls.verify-hostnames Whether to verify Elasticsearch server hostnames.
elasticsearch.tls.keystore-path Path to the PEM or JKS key store.
elasticsearch.tls.truststore-path Path to the PEM or JKS trust store.
elasticsearch.tls.keystore-password Password for the key store.
elasticsearch.tls.truststore-password Password for the trust store.

elasticsearch.tls.keystore-path#

The path to the PEM or JKS key store. This file must be readable by the operating system user running Presto.

This property is optional.

elasticsearch.tls.truststore-path#

The path to PEM or JKS trust store. This file must be readable by the operating system user running Presto.

This property is optional.

elasticsearch.tls.keystore-password#

The key password for the key store specified by elasticsearch.tls.keystore-path.

This property is optional.

elasticsearch.tls.truststore-password#

The key password for the trust store specified by elasticsearch.tls.truststore-path.

This property is optional.

Data Types#

The data type mappings are as follows:

Elasticsearch Presto
binary VARBINARY
boolean BOOLEAN
double DOUBLE
float REAL
byte TINYINT
short SMALLINT
integer INTEGER
long BIGINT
keyword VARCHAR
text VARCHAR
date TIMESTAMP
ip IPADDRESS
(all others) (unsupported)

Array Types#

Fields in Elasticsearch can contain zero or more values , but there is no dedicated array type. To indicate a field contains an array, it can be annotated in a Presto-specific structure in the _meta section of the index mapping.

For example, you can have an Elasticsearch index that contains documents with the following structure:

{
    "array_string_field": ["presto","is","the","besto"],
    "long_field": 314159265359,
    "id_field": "564e6982-88ee-4498-aa98-df9e3f6b6109",
    "timestamp_field": "1987-09-17T06:22:48.000Z",
    "object_field": {
        "array_int_field": [86,75,309],
        "int_field": 2
    }
}

The array fields of this structure can be defined by using the following command to add the field property definition to the _meta.presto property of the target index mapping.

curl --request PUT \
    --url localhost:9200/doc/_mapping \
    --header 'content-type: application/json' \
    --data '
{
    "_meta": {
        "presto":{
            "array_string_field":{
                "isArray":true
            },
            "object_field":{
                "array_int_field":{
                    "isArray":true
                }
            },
        }
    }
}'

Special Columns#

The following hidden columns are available:

Column Description
_id The Elasticsearch document ID
_score The document score returned by the Elasticsearch query
_source The source of the original document

Full Text Queries#

Presto SQL queries can be combined with Elasticsearch queries by providing the full text query as part of the table name, separated by a colon. For example:

SELECT * FROM "tweets: +presto SQL^2"

Pass-through Queries#

The Elasticsearch connector allows you to embed any valid Elasticsearch query, that uses the Elasticsearch Query DSL in your SQL query.

The results can then be used in any SQL statement, wrapping the Elasticsearch query. The syntax extends the syntax of the enhanced Elasticsearch table names with the following:

SELECT * FROM es.default."<index>$query:<es-query>"

The Elasticsearch query string es-query is base32-encoded to avoid having to deal with escaping quotes and case sensitivity issues in table identifiers.

The result of these query tables is a table with a single row and a single column named result of type VARCHAR. It contains the JSON payload returned by Elasticsearch, and can be processed with the built-in JSON functions.

AWS Authorization#

To enable AWS authorization using IAM policies, the elasticsearch.security option needs to be set to AWS. Additionally, the following options need to be configured appropriately:

Property Name Description
elasticsearch.aws.region AWS region or the Elasticsearch endpoint. This option is required.
elasticsearch.aws.access-key AWS access key to use to connect to the Elasticsearch domain.
elasticsearch.aws.secret-key AWS secret key to use to connect to the Elasticsearch domain.