Articles

Table Inheritance: What’s It Good For?

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Table inheritance is one of the most misunderstood — and powerful — features of PostgreSQL. With it, certain kinds of hard problems become easy. While many folks who have been bitten by table inheritance tend to avoid the feature, this blog post is intended to provide a framework for reasoning about when table inheritance is actually the right tool for the job.

Table inheritance is, to be sure, a power tool and thus something to use only when it brings an overall reduction in complexity to the design. Moreover, the current documentation doesn’t provide a lot of guidance regarding what the tool actually helps with and where are the performance costs and because inheritance sits orthogonal to relational design, working this out individually is very difficult.

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Benchmarking RavenDB Bulk Insert on Commodity Hardware

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We got a few requests for some guidance on how to optimize the RavenDB insert rate. Our current benchmark is standing at 135,000 inserts/sec on a sustained basis on a machine that costs less than $1,000. However, some users tried to write their own benchmarks and got far less (about 50,000 writes/sec). Therefore, in this post, I’m going to do a bunch of things and see if I can make RavenDB write really fast.

I’m going to be writing this post as I’m building the benchmark and testing things out. So, you’ll get a stream of consciousness. Hopefully it will make sense.

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Nacos as a Config Server

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Config servers are widely used in microservices architectures as placeholders for configurations. They also provide a centralized repository for users to manage configs for multiple applications.

Today, we are going to look at an example of how to use Nacos as a config server with Spring Cloud for Alibaba. The example is a Spring Boot application, running a Nacos server locally.

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Building a Chatbot With Couchbase, Amazon Lex, and Node.js

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It is no question that the future is going to be automated. We have automated self-driving vehicles, voice assistants, call center and text-based bots, and so much more. However, what does it take to bring automation to your business?

The short answer is that it doesn’t take much more than building standard applications if you’re using the right tools.

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Deploying a Java Application to an ECS Instance in Eclipse

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With the rapid development of cloud computing technology, an increasing number of developers are deploying applications to Alibaba Cloud Elastic Compute Service (ECS) instances. This tutorial describes how to deploy a Java application developed locally to an Alibaba Cloud ECS instance using Cloud Toolkit.

Develop an Application Locally

The coding method is similar — no matter whether you compile Java applications that run on the cloud or locally. Therefore, this article takes a Java servlet for printing "Hello World" on a web page as an example to explain the deployment method.

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Convert Payload From XML to Array of Objects by Comparing Mule 3 and Mule 4 Written Data Weave

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Hello everyone, in this article, I’m going to share my experience of when I tried to do a conversion in Mule 4. I will briefly explain the purpose of this article while showing the code that I can implement in Mule 3 and how I have to write it in Mule 4 in order to get a similar response.

As we all know, Mule 4 is trending in the market, which makes Mule 3 people migrate their code from Mule 3 to Mule 4. 

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Counting Distinct Users in Real-Time With Redis Using Low Memory

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If you are developing an event-based application that handles many requests from different users, you most likely want to count distinct user action within a sliding window or a specified time range.

One of the quickest ways to count distinct user is to prepare an SQL like SELECT count(distinct user) from ACTION_TABLE. But, this might be expensive if there are millions of records produced in real time.

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Awesome Asciidoctor: Don’t Wrap Lines in All Listing or Literal Blocks of Document

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In a previous post, we learned about setting the value of options attribute to nowrap on listing and literal blocks, so the lines in the block are not wrapped. In the comments, a user suggested another option to disable line wrapping for all listing and literal blocks in the document by using the document attribute prewrap. We must negate the document attribute, :prewrap!:, to disable all wrapping. If we place this document attribute at the top of our Asciidoctor document, it is applied for the whole document. We can also place it at other places in the document to change the setting for all listing and literal blocks following the prewrap document attribute. To enable wrapping again, we set :prewrap: (leaving out the exclamation mark).

In the following example, we have markup with a listing, literal, and example block, and we use the document attribute :prewrap!: to disable the wrapping for the listing and literal blocks:

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Database Delivery With Docker and SQL Change Automation

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See the basics of how to automate database builds into a Linux SQL Server container running on Windows and then back up the containerized database and restore it into dedicated containerized development copies for each developer and tester.

An obvious use for Docker images of SQL Server is to run up a working database from a backup quickly, maybe to test it or possibly to mask the data. We’ll start by doing that in this article. We’ll then use SQL Change Automation (SCA) to synchronize an empty copy of a development database in a Docker container with the latest build in source control and fill it with data ready for testing. Finally, we’ll do a backup of the containerized database so we can restore it into each developer’s local container. These techniques, combined with ‘glue scripts,’ can be used for supporting continuous delivery of databases.

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Securing REST APIs With Client Certificates

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This post is about an example of securing a REST API with a client certificate (a.k.a. X.509 certificate authentication).

In other words, a client verifies a server according to its certificate and the server identifies that client according to a client certificate (so-called mutual authentication).

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