Implementation:Apache Druid DemoQueries

Knowledge Sources	Apache_Druid
Domains	Web Console, Query Workbench
Last Updated	2026-02-10 10:00 GMT

Overview

Defines a set of demo SQL queries for the Apache Druid web console workbench, showcasing the sql-msq-task engine's ingestion and query capabilities.

Description

This module exports a getDemoQueries() function that returns an array of TabEntry objects, each containing a pre-configured WorkbenchQuery with a demo SQL query string. The demos form a progressive tutorial that guides users through the multi-stage query (MSQ) task engine features: basic data ingestion from external sources, data transformation with rollup, data enrichment via JOINs, re-ingestion from existing datasources, data filtering/deletion, inline SELECT queries, and large-scale sorting. All queries use a base context of maxNumTasks: 2.

Usage

Called by the workbench view to populate the demo tabs when the user activates the demo mode. Each returned TabEntry becomes a separate query tab in the workbench editor.

Code Reference

Source Location

• Repository: Apache Druid
• File: web-console/src/views/workbench-view/demo-queries.ts
• Lines: 1-306

Signature

export function getDemoQueries(): TabEntry[]

Import

import { getDemoQueries } from './demo-queries';

I/O Contract

Inputs

Name	Type	Required	Description
(none)	-	-	This function takes no parameters.

Outputs

Name	Type	Description
TabEntry[]	TabEntry[]	An array of 7 demo tab entries, each with an id, tabName, and a WorkbenchQuery containing a SQL query string and context configuration.

Usage Examples

Loading Demo Queries into the Workbench

import { getDemoQueries } from './demo-queries';

const demoTabs = getDemoQueries();
// demoTabs is an array of TabEntry objects:
// [
//   { id: 'demo1', tabName: 'Demo 1', query: WorkbenchQuery },
//   { id: 'demo2', tabName: 'Demo 2', query: WorkbenchQuery },
//   ...
//   { id: 'demo6', tabName: 'Demo 6', query: WorkbenchQuery },
// ]

Demo Query Descriptions

Demo	Title	Engine	Description
Demo 1	Basic Ingestion	sql-msq-task (default)	Reads a JSON file from an HTTP source using TABLE(EXTERN(...)) and writes it into the kttm_simple datasource using REPLACE INTO ... OVERWRITE ALL. Demonstrates the simplest possible ingestion (SELECT *).
Demo 2	Rollup Ingestion	sql-msq-task (default)	Builds on Demo 1 by selecting specific columns, parsing timestamps, filtering rows (iOS only), applying GROUP BY for rollup with aggregates (COUNT, SUM, APPROX_COUNT_DISTINCT_DS_HLL), and using PARTITIONED BY HOUR with CLUSTERED BY.
Demo 3	JOIN Enrichment	sql-msq-task (default)	Extends Demo 2 by JOINing with an external TSV file (country lookup) to add Capital and ISO3 columns. Also demonstrates computed columns (browser_major via REGEXP_EXTRACT).
Demo 4a	Re-ingestion from Druid	sql-msq-task (default)	Same transformation as Demo 3, but reads from the kttm_simple datasource (created in Demo 1) instead of external data. Demonstrates mixing Druid tables with external data sources.
Demo 4b	Data Deletion	sql-msq-task (default)	Reads from and writes to the same datasource (kttm_simple), filtering out all rows for 'New Zealand'. Demonstrates in-place data transformation.
Demo 5	Inline SELECT	sql-msq-task (default)	Runs a SELECT query without REPLACE/INSERT, computing aggregates (COUNT DISTINCT) across external data with JOINs. Demonstrates the MSQ engine for ad-hoc queries.
Demo 6	Large-Scale Sorting	sql-msq-task (explicit)	Re-sorts the kttm_simple datasource on arbitrary columns (session, number). Demonstrates sorting capabilities that are not possible with the native SQL engine.

Internals

Base Query Configuration

All demo queries are built from a base WorkbenchQuery with:

const BASE_QUERY = WorkbenchQuery.blank().changeQueryContext({ maxNumTasks: 2 });

This limits the MSQ engine to 2 concurrent tasks, suitable for demo/testing environments.

Data Sources Used

• External HTTP: https://static.imply.io/example-data/kttm-v2/kttm-v2-2019-08-25.json.gz (JSON format)
• External HTTP: https://static.imply.io/example-data/lookup/countries.tsv (TSV format)
• Druid datasource: kttm_simple (created by Demo 1, used by Demos 4a, 4b, 6)

Demo 6 Engine Override

Demo 6 is the only demo that explicitly sets the engine to sql-msq-task via .changeEngine('sql-msq-task'), as it runs a SELECT without INSERT/REPLACE which would otherwise default to the native engine.

Related Pages

• Environment:Apache_Druid_Web_Console_Development