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Tag Archives: PostgreSQL

Reactive Programming and Relational Databases

Imperative code eats threads at the pace of incoming requests while Software is eating the world. This post discusses the assumptions for reactive programming on the JVM and what this means for integrations – in particular, relational databases. The motivation to come up with a post is the constant increase in reactive programming adoption while some major building blocks are not yet available ...

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How to map PostgreSQL Enums to JPA entity properties using Hibernate

Introduction The open-source hibernate-types project allows you to map JSON, ARRAY, YearMonth, Month or database-specific columns (e.g. INET addresses). In this article, we are going to see how you can map a PostgreSQL Enum type to a Java array when using JPA and Hibernate. Maven dependency First of all, you need to set up the following Maven dependency in your ...

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PostgreSQL on Open Liberty

Open Liberty is an interesting new OSS Java EE application server that originated from WebSphere Liberty. You can configure Open Liberty to use PostgreSQL as its default data source as follows: Add directives for <datasource>, <jdbcDriver>, and <library> to the server.xml configuration: <?xml version="1.0" encoding="UTF-8"?> <server description="OpenLiberty Java EE 8 Server"> <featureManager> <feature>javaee-7.0</feature> </featureManager> <httpEndpoint id="defaultHttpEndpoint" host="*" httpPort="9080" httpsPort="9443"/> <keyStore ...

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Tuning PostgreSQL with pgbench

When it comes to performance tuning an environment, often the first place to start is with the database. The reason for this is that most applications rely very heavily on a database of some sort. Unfortunately, databases can be one of the most complex areas to tune. The reason I say that is because tuning a database service properly often ...

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More on Spooling Queries and Results in psql

In the recent blog post SPOOLing Queries with Results in psql, I looked briefly at some PostgreSQL database psql meta-commands and options that can be used to emulate Oracle database‘s SQL*Plus spooling behavior. In that post, I wrote, “I have not been able to figure out a way to … have both the query and its results written to the ...

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AutoCommit in PostgreSQL’s psql

One potential surprise for someone familiar with Oracle database‘s SQL*Plus when being introduced to PostgreSQL database‘s psql may be psql‘s default enabling of autocommit. This post provides an overview of psql’s handling of autocommit and some related nuances. By default, Oracle’s SQL*Plus command-line tool does not automatically commit DML statements and the operator must explicitly commit these statements as part ...

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Does PostgreSQL Have an ORA-01795-like Limit?

The Oracle database requires that no more than 1000 entries be used in a SQL IN portion of a WHERE clause and will throw an ORA-01795 error if that number is exceeded. If a value needs to be compared to more than 1000 values, approaches other than use of IN must be applied. I wondered if this limitation applies to ...

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NoSQL vs. SQL: Choosing a Data Management Solution

Table Of Contents 1. Introduction 2. Distributed systems: the CAP theorem 3. Relational data stores 3.1. MySQL / MariaDB 3.2. PostgreSQL 3.3. Others 4. Why NoSQL? 5. Key/Value data stores 5.1. DynamoDB 5.2. Memcached 5.3. Redis 5.4. Riak 5.5. Aerospike 5.6. FoundationDB 6. Columnar data stores 6.1. Accumulo 6.2. Cassandra 6.3. HBase 7. Graph data stores 7.1. Neo4J 7.2. Titan ...

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Listen to notifications from Postgresql with Scala

In the past I’ve written a couple of articles (Building a REST service in Scala with Akka HTTP, Akka Streams and reactive mongo and ReactiveMongo with Akka, Scala and websockets) which used MongoDB to push updates directly from the database to a Scala application. This is a very nice feature if you just want to subscribe your application to a ...

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