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index Quickstart (local)

This quickstart gets you started with Apache Druid and introduces you to Druid ingestion and query features. For this tutorial, we recommend a machine with at least 6 GB of RAM.

In this quickstart, you'll do the following:

  • install Druid
  • start up Druid services
  • use SQL to ingest and query data

Druid supports a variety of ingestion options. Once you're done with this tutorial, refer to the Ingestion page to determine which ingestion method is right for you.

Requirements

You can follow these steps on a relatively modest machine, such as a workstation or virtual server with 16 GiB of RAM.

Druid comes equipped with launch scripts that can be used to start all processes on a single server. Here, we will use auto, which automatically sets various runtime properties based on available processors and memory.

In addition, Druid includes several bundled non-automatic profiles for a range of machine sizes. These range from nano (1 CPU, 4GiB RAM) to x-large (64 CPU, 512GiB RAM). We won't use those here, but for more information, see Single server deployment. For additional information on deploying Druid services across clustered machines, see Clustered deployment.

The software requirements for the installation machine are:

Druid relies on the environment variables JAVA_HOME or DRUID_JAVA_HOME to find Java on the machine. You can set DRUID_JAVA_HOME if there is more than one instance of Java. To verify Java requirements for your environment, run the bin/verify-java script.

Before installing a production Druid instance, be sure to review the security overview. In general, avoid running Druid as root user. Consider creating a dedicated user account for running Druid.

Install Druid

Download the {{DRUIDVERSION}} release from Apache Druid.

In your terminal, extract the file and change directories to the distribution directory:

tar -xzf apache-druid-{{DRUIDVERSION}}-bin.tar.gz
cd apache-druid-{{DRUIDVERSION}}

The distribution directory contains LICENSE and NOTICE files and subdirectories for executable files, configuration files, sample data and more.

Start up Druid services

Start up Druid services using the auto single-machine configuration. This configuration includes default settings that are appropriate for this tutorial, such as loading the druid-multi-stage-query extension by default so that you can use the MSQ task engine.

You can view that setting and others in the configuration files in the conf/druid/auto.

From the apache-druid-{{DRUIDVERSION}} package root, run the following command:

./bin/start-druid

This brings up instances of ZooKeeper and the Druid services and may use up to 80% of the total available system memory. To explicitly set the total memory available to Druid, pass a value for the memory parameter, e.g. ./bin/start-druid -m 16g or ./bin/start-druid --memory 16g.

$ ./bin/start-druid
[Tue Nov 29 16:31:06 2022] Starting Apache Druid.
[Tue Nov 29 16:31:06 2022] Open http://localhost:8888/ in your browser to access the web console.
[Tue Nov 29 16:31:06 2022] Or, if you have enabled TLS, use https on port 9088.
[Tue Nov 29 16:31:06 2022] Starting services with log directory [/apache-druid-{{DRUIDVERSION}}/log].
[Tue Nov 29 16:31:06 2022] Running command[zk]: bin/run-zk conf
[Tue Nov 29 16:31:06 2022] Running command[broker]: bin/run-druid broker /apache-druid-{{DRUIDVERSION}}/conf/druid/single-server/quickstart '-Xms1187m -Xmx1187m -XX:MaxDirectMemorySize=791m'
[Tue Nov 29 16:31:06 2022] Running command[router]: bin/run-druid router /apache-druid-{{DRUIDVERSION}}/conf/druid/single-server/quickstart '-Xms128m -Xmx128m'
[Tue Nov 29 16:31:06 2022] Running command[coordinator-overlord]: bin/run-druid coordinator-overlord /apache-druid-{{DRUIDVERSION}}/conf/druid/single-server/quickstart '-Xms1290m -Xmx1290m'
[Tue Nov 29 16:31:06 2022] Running command[historical]: bin/run-druid historical /apache-druid-{{DRUIDVERSION}}/conf/druid/single-server/quickstart '-Xms1376m -Xmx1376m -XX:MaxDirectMemorySize=2064m'
[Tue Nov 29 16:31:06 2022] Running command[middleManager]: bin/run-druid middleManager /apache-druid-{{DRUIDVERSION}}/conf/druid/single-server/quickstart '-Xms64m -Xmx64m' '-Ddruid.worker.capacity=2 -Ddruid.indexer.runner.javaOptsArray=["-server","-Duser.timezone=UTC","-Dfile.encoding=UTF-8","-XX:+ExitOnOutOfMemoryError","-Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager","-Xms256m","-Xmx256m","-XX:MaxDirectMemorySize=256m"]'

All persistent state, such as the cluster metadata store and segments for the services, are kept in the var directory under the Druid root directory, apache-druid-{{DRUIDVERSION}}. Each service writes to a log file under var/sv.

At any time, you can revert Druid to its original, post-installation state by deleting the entire var directory. You may want to do this, for example, between Druid tutorials or after experimentation, to start with a fresh instance.

To stop Druid at any time, use CTRL+C in the terminal. This exits the bin/start-druid script and terminates all Druid processes.

Open the web console

After the Druid services finish startup, open the web console at http://localhost:8888.

web console

It may take a few seconds for all Druid services to finish starting, including the Druid router, which serves the console. If you attempt to open the web console before startup is complete, you may see errors in the browser. Wait a few moments and try again.

In this quickstart, you use the the web console to perform ingestion. The MSQ task engine specifically uses the Query view to edit and run SQL queries. For a complete walkthrough of the Query view as it relates to the multi-stage query architecture and the MSQ task engine, see UI walkthrough.

Load data

The Druid distribution bundles the wikiticker-2015-09-12-sampled.json.gz sample dataset that you can use for testing. The sample dataset is located in the quickstart/tutorial/ folder, accessible from the Druid root directory, and represents Wikipedia page edits for a given day.

Follow these steps to load the sample Wikipedia dataset:

  1. In the Query view, click Connect external data.

  2. Select the Local disk tile and enter the following values:

    • Base directory: quickstart/tutorial/

    • File filter: wikiticker-2015-09-12-sampled.json.gz

    Data location

    Entering the base directory and wildcard file filter separately, as afforded by the UI, allows you to specify multiple files for ingestion at once.

  3. Click Connect data.

  4. On the Parse page, you can examine the raw data and perform the following optional actions before loading data into Druid:

    • Expand a row to see the corresponding source data.
    • Customize how the data is handled by selecting from the Input format options.
    • Adjust the primary timestamp column for the data. Druid requires data to have a primary timestamp column (internally stored in a column called __time). If your dataset doesn't have a timestamp, Druid uses the default value of 1970-01-01 00:00:00.

    Data sample

  5. Click Done. You're returned to the Query view that displays the newly generated query. The query inserts the sample data into the table named wikiticker-2015-09-12-sampled.

    Show the query 
    REPLACE INTO "wikiticker-2015-09-12-sampled" OVERWRITE ALL
WITH input_data AS (SELECT *
FROM TABLE(
  EXTERN(
    '{"type":"local","baseDir":"quickstart/tutorial/","filter":"wikiticker-2015-09-12-sampled.json.gz"}',
    '{"type":"json"}',
    '[{"name":"time","type":"string"},{"name":"channel","type":"string"},{"name":"cityName","type":"string"},{"name":"comment","type":"string"},{"name":"countryIsoCode","type":"string"},{"name":"countryName","type":"string"},{"name":"isAnonymous","type":"string"},{"name":"isMinor","type":"string"},{"name":"isNew","type":"string"},{"name":"isRobot","type":"string"},{"name":"isUnpatrolled","type":"string"},{"name":"metroCode","type":"long"},{"name":"namespace","type":"string"},{"name":"page","type":"string"},{"name":"regionIsoCode","type":"string"},{"name":"regionName","type":"string"},{"name":"user","type":"string"},{"name":"delta","type":"long"},{"name":"added","type":"long"},{"name":"deleted","type":"long"}]'
     )
   ))
SELECT
  TIME_PARSE("time") AS __time,
  channel,
  cityName,
  comment,
  countryIsoCode,
  countryName,
  isAnonymous,
  isMinor,
  isNew,
  isRobot,
  isUnpatrolled,
  metroCode,
  namespace,
  page,
  regionIsoCode,
  regionName,
  user,
  delta,
  added,
  deleted
FROM input_data
PARTITIONED BY DAY

  6. Optionally, click Preview to see the general shape of the data before you ingest it.

  7. Edit the first line of the query and change the default destination datasource name from wikiticker-2015-09-12-sampled to wikipedia.

  8. Click Run to execute the query. The task may take a minute or two to complete. When done, the task displays its duration and the number of rows inserted into the table. The view is set to automatically refresh, so you don't need to refresh the browser to see the status change.

    Run query

    A successful task means that Druid data servers have picked up one or more segments.

Query data

Once the ingestion job is complete, you can query the data.

In the Query view, run the following query to produce a list of top channels:

SELECT
  channel,
  COUNT(*)
FROM "wikipedia"
GROUP BY channel
ORDER BY COUNT(*) DESC

Query view

Congratulations! You've gone from downloading Druid to querying data with the MSQ task engine in just one quickstart.

Next steps

See the following topics for more information:

Remember that after stopping Druid services, you can start clean next time by deleting the var directory from the Druid root directory and running the bin/start-druid script again. You may want to do this before using other data ingestion tutorials, since they use the same Wikipedia datasource.