Future Technology

Question Actual-Time Information With GraphQL and Streaming Database

7 min read

In fashionable software improvement, effectively querying and retrieving real-time knowledge is essential to constructing sturdy and performant techniques. Utilizing materialized views we will enhance question efficiency. When it’s mixed with GraphQL and a steaming database, we will outline our queries to leverage these materialized views for the information that consistently adjustments.

For instance, social media platforms like Twitter produce an enormous quantity of information each second. This knowledge is effective for analyzing developments and consumer conduct. On this article, we’ll discover how integrating GraphQL, materialized views, and streaming databases such RisingWave can allow us to effectively question tweets and discover the hottest hashtags in real-time.

Earlier than diving into implementation, it is very important perceive these 3 ideas (GraphQL, materialized view, and streaming database). I consider you’re sensible sufficient to make use of Google or ChatGPT to seek out out this info. Nonetheless, I’m going to clarify shortly why this integration might be useful and the position of every within the subsequent part.

Materialized Views as Precomputed Caches

With a materialized view, we can precompute and store the results of frequently executed SQL queries. It is a denormalized representation of the data, which means that complex joins and aggregations are already performed and stored in a database like PostgreSQL. This simplifies the question logic required to retrieve knowledge and eliminates the necessity for us to manually deal with be a part of operations. In Twitter’s case, materialized views can be utilized to compute summaries of consumer exercise, such because the variety of followers, a hashtag used, likes, or feedback.

GraphQL to Retrieve Exactly What Data We Need

GraphQL allows us to specify exactly what data we need and receive it in a single request without using an additional programming-language-specific data-processing framework or defining a bunch of entity objects and endpoints in the case of REST(Representational State Transfer). Unlike REST, GraphQL significantly reduces the number of round trips, resulting in faster data fetching. With GraphQL, we can directly access the materialized views in the database through the defined schema, abstracting away the complexities of the underlying database structure. A social media analytics platform can leverage GraphQL to offer a flexible API for querying and analyzing user-generated content.

There are several popular GraphQL builders and frameworks available that can assist in building GraphQL APIs. You can connect to different data sources and integrate with popular databases like PostgreSQL, and MySQL. Here are some of the widely used ones:

StepZen is a platform to construct and deploy GraphQL APIs that integrates and combination knowledge from numerous sources. Within the demo part, I’ll present easy methods to construct a GraphQL API in declarative code utilizing StepZen.

Streaming Database to Process Real-Time Data

To leverage the full potential of real-time data querying with GraphQL, a streaming database can be utilized. Materialized views may not always contain the most up-to-date data since they depend on when and how often the view is refreshed. Traditional databases such as PostgreSQL support materialized views, but to see the query over time, you need to rerun the same query — and again. To get updated results, you need to execute queries repeatedly, while a streaming database like RisingWave does almost all of its work at write time. This post explains how a streaming database differs from a conventional database. When knowledge flows into the streaming database, it’s processed and instantly used to replace the prevailing materialized views. It will possibly ingest knowledge from numerous data sources like Kafka or Pulsar. By combining GraphQL with a streaming database, we will constantly ingest incoming tweet posts and replace the materialized views in actual time and question adjustments in knowledge immediately.

Query Twitter Events Demo

Once we understand the importance of GraphQL, materialized views, and a streaming database, we can use this combination to create a new way to access tweet data. By pre-calculating summaries of the data and exposing them through a GraphQL endpoint, we can quickly get valuable insights from the tweets.

Before You Begin

In this tutorial, we will leverage the existing use case demo of RisingWave on the website called Fast Twitter Events Processing. Be sure you accomplished the tutorial by cloning, launching the demo mission there utilizing Docker, connecting RisingWave to Kafka knowledge streams, and defining a materialized view because the tutorial guides you.

Different stipulations to put in are:

When You Are Ready

Now I assume that you configured RisingWave and we have a materialized view named hot_hashtags processed by the RisingWave that tracks how often each hashtag is used daily on Twitter. In the next steps, we install and set up StepZen, design the GraphQL schema, map GraphQL queries to the precise knowledge within the materialized view, and at last, expose the GraphQL Endpoint.

Step 1: Install StepZen CLI

Note that you can also follow the instructions on StepZen website to install and run it. The StepZen command-line interface (CLI) provides commands to set up and manage StepZen. Run the following command to install the StepZen CLI:

npm install -g stepzen

Step 2: Run StepZen in Docker

Next, we run the StepZen service on your local machine using the StepZen CLI we installed in the previous step:

stepzen service start

To use the StepZen CLI for local development, you must log in by pointing the CLI to the local configuration. Simply run the following command after StepZen service started:

stepzen login --config ~/.stepzen/stepzen-config.local.yaml

Step 3: Clone the graphql-stepzen-risingwave Demo Project

Find my repository called graphql-stepzen-risingwave-demo on GitHub. Git clone this repository onto your machine. This mission already has all the things you want. There’s written schema code in a postgresql.graphql GraphQL Schema Definition Language (SDL) file with sorts and queries outlined for the materialized view hot_hashtags within the RisingWave database. It has additionally a stepzen.config.json file with our GraphQL endpoint.

git clone
cd graphql-stepzen-risingwave-demo

Step 4: Create a Ngrok Account and Install Ngrok (Optional)

Note that it is just an additional step if you are running StepZen and RisingWave in your local environment. In the case of cloud or running instances in your server which can be accessible through the web, you’ll be able to set a direct tackle of RisingWave within the StepZen database configuration. In case you are operating each StepZen and RisingWave inside Docker containers, you’ll be able to specify the tackle of host.docker.inside.

Ngrok is a instrument that creates a safe tunnel between a public web tackle and an area server operating in your machine. Create an account for ngrok and just be sure you can entry it by setting authtoken. To make the RisingWave database out there to different companies exterior your personal community, you should create a TCP tunnel. For this ngrok can be used on the port the place RisingWave is operating 4566:

ngrok tcp 4566

After you run the command, ngrok will return the forwarding tackle for the native RisingWave database, which can look one thing like this:

You want to add this to the file ./config.yaml within the demo mission the place you should exchange ngrok_tunnel together with your tackle

  - configuration:
      title: postgresql_config
      uri: postgresql://

Step 5: Run GraphQL Endpoint

By operating the command stepzen begin, you’ll be able to deploy the GraphQL schema we now have in postgresql.graphql file to StepZen. This immediately creates a GraphQL API within the localhost, accessible by way of the configured endpoint (api/twitter) in stepzen.config.json file. When you navigate to http://localhost:5001/api/twitter, you will notice the StepZen dashboard explorer in your browser.

StepZen dashboard explorer

Step 6: Query the Materialized View

StepZen Explorer shows available queries with their attributes. When you run the following query getHotHashtags, it will pull data from the RisingWave materialized view and shows returned data in the explorer.

query MyQuery 

See the output:

If you open the postgresql.graphql file, you will notice how I used the GraphQL directive @dbquery to attach the database and write an SQL question to pick the TOP 10 fashionable hashtags.

kind Question 
  getHotHashtags: [hot_hashtags]
      kind: "postgresql"
      question: """
        ORDER BY
            hashtag_occurrences DESC
      configuration: "postgresql_config"

Subsequent Steps

Up to now, we now have constructed and deployed a GraphQL API api/twitter with the database backend. Subsequent, you’ll be able to observe easy methods to eat real-time knowledge from other sources than Kafka with RisingWave, mix multiple streams of data, create materialized views on joined streams, and create a sequence of queries with StepZen.


With StepZen GraphQL API, we simplified knowledge entry with out introducing a backend service to do that work and we mixed it with the real-time updates supplied by RisingWave. In abstract, querying real-time knowledge with GraphQL and the streaming database opens up new prospects for creating extremely responsive and interactive purposes.

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