How to combine source fields into one column

In this recipe we'll learn how to combine the data from fields in our data source into a single column in Apache Pinot.

note

Pinot Version	0.10.0
Code	startreedata/pinot-recipes/combine-fields

Pre-requisites

You will need to install Docker locally to follow the code examples in this guide.

Download Recipe

First, clone the GitHub repository to your local machine and navigate to this recipe:

git clone git@github.com:startreedata/pinot-recipes.git
cd pinot-recipes/recipes/combine-fields

If you don't have a Git client, you can also download a zip file that contains the code and then navigate to the recipe.

Launch Pinot Cluster

You can spin up a Pinot Cluster by running the following command:

docker-compose up

This command will run a single instance of the Pinot Controller, Pinot Server, Pinot Broker, and Zookeeper. You can find the docker-compose.yml file on GitHub.

Dataset

We're going to import the following JSON file:

data/movies.json

{"name":"Pete", "surname": "Smith"}
{"name":"John", "surname": "Jones"}

Pinot Schema and Table

Now let's create a Pinot Schema and Table.

First, the schema:

config/schema.json

{
  "schemaName": "people",
  "dimensionFieldSpecs": [
    {
      "name": "fullName",
      "dataType": "STRING"
    }
  ]
}

You can create the schema by running the following command:

docker exec -it pinot-controller-json bin/pinot-admin.sh AddSchema \
  -schemaFile /config/schema.json \
  -exec

We'll also have the following table config:

config/table.json

{
  "tableName": "people",
  "tableType": "OFFLINE",
  "segmentsConfig": {
    "replication": 1,
    "schemaName": "people"
  },
  "ingestionConfig": {
    "transformConfigs": [
      {
        "columnName": "fullName",
        "transformFunction": "concat(name, surname, ' ')"
      }
    ],
    "batchIngestionConfig": {
      "segmentIngestionType": "APPEND",
      "segmentIngestionFrequency": "DAILY"
    }
  },
  "tenants": {
    "broker": "DefaultTenant",
    "server": "DefaultTenant"
  },
  "tableIndexConfig": {
    "loadMode": "MMAP"
  },
  "metadata": {}
}

The highlighted section contains a transformation function that concatenates the name and surname fields, separated by a space.

You can create the table by running the following command:`

docker exec -it pinot-controller-json bin/pinot-admin.sh AddTable \
  -tableConfigFile /config/table.json \
  -exec

Ingestion Job

Now we’re going to import the JSON file into Pinot. We'll do this with the following ingestion spec:

config/job-spec.yml

executionFrameworkSpec:
  name: 'standalone'
  segmentGenerationJobRunnerClassName: 'org.apache.pinot.plugin.ingestion.batch.standalone.SegmentGenerationJobRunner'
  segmentTarPushJobRunnerClassName: 'org.apache.pinot.plugin.ingestion.batch.standalone.SegmentTarPushJobRunner'
jobType: SegmentCreationAndTarPush
inputDirURI: '/data'
includeFileNamePattern: 'glob:**/import.json'
outputDirURI: '/opt/pinot/data/people/'
overwriteOutput: true
pinotFSSpecs:
  - scheme: file
    className: org.apache.pinot.spi.filesystem.LocalPinotFS
recordReaderSpec:
  dataFormat: 'json'
  className: 'org.apache.pinot.plugin.inputformat.json.JSONRecordReader'
tableSpec:
  tableName: 'people'
pinotClusterSpecs:
  - controllerURI: 'http://localhost:9000'

You can run the following command to run the import:

docker exec -it pinot-controller-json bin/pinot-admin.sh LaunchDataIngestionJob \
  -jobSpecFile /config/job-spec.yml

Querying

Once that's completed, navigate to localhost:9000/#/query and click on the people table or copy/paste the following query:

select * 
from people 

You will see the following output:

fullName
Pete Smith
John Jones

Query Results

We can see that the name and surname fields from our JSON file have been combined into a single fullName column for each person.