Tag Archives: JDBC

Previously we set up two EntityManagers in the same application. One for the reads and one for the writes. Now it’s time to create our read repository. The read only repository will use the secondary read only EntityManager. In order to make it a read only repository, it is essential not to have any save and persist actions. 01 02 ...

Our previous setup works as expected. What we shall do now is to get one step further and configure two separate entity managers without affecting the functionality we achieved previously. The first step would be to set the default entity manager configuration to a primary one.This is the first step 01 02 03 04 05 06 07 08 09 10 ...

In our previous post we set up multiple PostgreSQL instances with the same data.Our next step would be to configure our spring project by using the both servers. As stated previously we shall use some of the code taken from the Spring Boot JPA post, since we use exactly the same database. This shall be our gradle build file 01 ...

This is a series of blog posts on our quest to increase our application’s performance by utilizing read replicas. For this project our goal is to set up our spring data application and use read repositories for writes and repositories based on read replicas for reads. In order to simulate this environment we shall use PostgreSQL instances through Docker. The ...

Probably each of us encountered this problem at least once in the programmer’s life – how to emulate a database sequence? Below you may find my variation of this problem’s solution. Suppose that we have an interface defining the desired API for returning a sequence of integer numbers: 1 2 3 4 5 public interface Sequences {       int nextValue(String ...

In my previous post, I showed how to convert a java.sql.ResultSet to JSON and stream it back to the caller. This post, is about streaming it in CSV format instead. Streaming allows you to transfer the data, little by little, without having to load it all into the server’s memory. For example, consider the following ResultSet: +---------+-----+ | Name | ...

We do use a lot of h2 with spring especially for unit tests. However instead of unit tests we might want to have a fully functional prototype with data to display. H2 is the perfect candidate for that, it works great with spring, it has good syntax compatibility with most databases out there and it also provides you with a ...

This post shows how you can convert a java.sql.ResultSet to JSON and stream it back to the caller. This is useful if you want to send a large dataset from a JDBC DataSource to a web application in JSON format. Streaming allows you to transfer the data, little by little, without having to load it all into the server’s memory. ...

In web applications, user session management is very crucial for managing user state. In this article, we are going to learn about what are the approaches we have been following to manage user sessions in a clustered environment and how we can use Spring Session to implement it in a much simpler and more scalable way. Typically in production environments, we will ...