tElasticSearchLookupInput - 6.1

Talend Components Reference Guide

EnrichVersion
6.1
EnrichProdName
Talend Big Data
Talend Big Data Platform
Talend Data Fabric
Talend Data Integration
Talend Data Management Platform
Talend Data Services Platform
Talend ESB
Talend MDM Platform
Talend Open Studio for Big Data
Talend Open Studio for Data Integration
Talend Open Studio for Data Quality
Talend Open Studio for ESB
Talend Open Studio for MDM
Talend Real-Time Big Data Platform
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

Function

tElasticSearchLookupInput extracts data based on a query from ElasticSearch.

Purpose

tElasticSearchLookupInput executes a ElasticSearch query with a strictly defined order which must correspond to the schema definition.

It passes on the extracted data to tMap in order to provide the lookup data to the main flow. It must be directly connected to a tMap component and requires this tMap to use Reload at each row or Reload at each row (cache) for the lookup flow.

tElasticSearchLookupInput properties in Spark Streaming Jobs

Component family

ElasticSearch

 

Basic settings

Schema and Edit Schema

A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. The schema is either Built-In or stored remotely in the Repository.

 

Use an existing configuration

Select this check box and in the Component List click the relevant connection component to reuse the connection details you already defined.

 

Transport addresses

Enter the addresses of the ElasticSearch nodes you need the component to connect to.

Different from tElasticSearchOutput which uses ElasticSearch Node Client, tElasticSearchLookupInput uses ElasticSearch Transport Client to connect to the ElasticCluster cluster. This allows tElasticSearchLookupInput to quickly create multiple connections to the cluster.

For further information about the ElasticSearch Node Client and the ElasticSearch Transport Client, see https://www.elastic.co/guide/en/elasticsearch/guide/current/_transport_client_versus_node_client.html.

 

Cluster name

Enter the name the ElasticSearch cluster to be used.

The Cluster name parameter is mandatory and eventually taken into account only when the ElasticSearch component to be connected to ElasticSearch is tElasticSearchLookupInput.

For further information about the ElasticSearch Node Client and the ElasticSearch Transport Client, see https://www.elastic.co/guide/en/elasticsearch/guide/current/_transport_client_versus_node_client.html.

 

Index

Enter the name of the index you want to read documents from.

An index is the largest unit of storage in the Elastisearch system.

 

Type

Enter the name of the type the documents to be read belong to.

For example, blogpost_en and blogpost_fr can be two types that represent given English blog posts and French blog posts, respectively.

You can dynamically uses the values of a given column to be document types. If you need to do so, enter the name of that column into a pair of braces ({}), for example, {blog_author}.

 

Query

Enter the ElasticSearch query to be performed by this component.

In editing queries, you need to use the syntax required by ElasticSearch along with escape characters required by Java, and put the query within double quotation marks.

For example, in the ElasticSearch documentation, an example query reads as follows:

es.query = { "query" : { "term" : { "user" : "costinl" } } }

In this Query field, you should write the same query in the following way:

"{ \"query\" : { \"term\" : {\"user\" : \"costinl\" } } }"

The schema of the main flow to tMap is available to use to construct the SQL statement in the current component.

Note that the result set from this lookup component must be filtered to only return rows that match the expected join key in tMap.

Advanced settings

Scroll time

Enter the time duration (in milliseconds) through which an input batch is progressively loaded from ElasticSearch.

This duration is useful only in case your query is bringing in huge batches. But since tMap in the streaming mode reloads data at each row, an appropriately written query should avoid producing huge batches.

 

Use SSL/TLS

Select this check box to enable the SSL or TLS encrypted connection.

Then you need to use the tSetKeystore component in the same Job to specify the authentication information.

For further information about tSetKeystore, see tSetKeystore.

 

Configuration

Add the parameters accepted by Elasticsearch to perform more customized actions.

For example, enter es.mapping.id in the Key column and true in the Value column to make the document field/property name contain the document id. Note that you must put double quotation marks around the entered information.

For a list of the parameters you can use, see https://www.elastic.co/guide/en/elasticsearch/hadoop/master/configuration.html.

 

Connection pool

In this area, you configure the connection pool used to control the number of connections that stay open simultaneously. Generally speaking, the default values given to the following connection pool parameters are good enough for most use cases.

  • Max total number of connections: enter the maximum number of connections (idle or active) that are allowed to stay open simultaneously.

    The default number is 8. If you enter -1, you allow unlimited number of open connections at the same time.

  • Max waiting time (ms): enter the maximum amount of time at the end of which the response to a demand for using a connection should be returned by the connection pool. By default, it is -1, that is to say, infinite.

  • Min number of idle connections: enter the minimum number of idle connections (connections not used) allowed in the connection pool.

  • Max number of idle connections: enter the maximum number of idle connections (connections not used) allowed in the connection pool.

 

Evict connections

Select this check box to define criteria to destroy connections in the connection pool. The following fields are displayed once you have selected it.

  • Time between two eviction runs: enter the time interval (in milliseconds) at the end of which the component checks the status of the connections and destroys the idle ones.

  • Min idle time for a connection to be eligible to eviction: enter the time interval (in milliseconds) at the end of which the idle connections are destroyed.

  • Soft min idle time for a connection to be eligible to eviction: this parameter works the same way as Min idle time for a connection to be eligible to eviction but it keeps the minimum number of idle connections, the number you define in the Min number of idle connections field.

Usage in Spark Streaming Jobs

In a Talend Spark Streaming Job, it is used as a start component and requires an output link. The other components used along with it must be Spark Streaming components, too. They generate native Spark code that can be executed directly in a Spark cluster.

This component should use a tElasticSearchConfiguration component present in the same Job to connect to ElasticSearch. You need to select the Use an existing configuration check box and then select the tElasticSearchConfiguration component to be used.

This component, along with the Spark Streaming component Palette it belongs to, appears only when you are creating a Spark Streaming Job.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs.

Log4j

If you are using a subscription-based version of the Studio, the activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User Guide.

For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.

Spark Connection

You need to use the Spark Configuration tab in the Run view to define the connection to a given Spark cluster for the whole Job. In addition, since the Job expects its dependent jar files for execution, one and only one file system related component from the Storage family is required in the same Job so that Spark can use this component to connect to the file system to which the jar files dependent on the Job are transferred:

This connection is effective on a per-Job basis.

Related scenarios

No scenario is available for the Spark Streaming version of this component yet.