# db-patterns

**Repository Path**: mirrors_bramp/db-patterns

## Basic Information

- **Project Name**: db-patterns
- **Description**: Some simple DB patterns implemented onto of MySQL
- **Primary Language**: Unknown
- **License**: BSD-2-Clause
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2020-08-08
- **Last Updated**: 2026-05-16

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

MySQL DB Patterns
=================
by [Andrew Brampton](http://bramp.net) 2013

Intro
-----

Some useful java code backed by JDBC that implements some common patterns.

So far a Condition object, and a Queue are implemented.

```maven
	<dependency>
		<groupId>net.bramp.db-patterns</groupId>
		<artifactId>db-patterns</artifactId>
		<version>0.1.1</version>
	</dependency>
```

Condition
---------

A distributed Java Condition

```java
  DataSource ds = ...
  Condition condition = new MySQLSleepBasedCondition(ds, "lockname");
  condition.await(); // Blocks until a notify
  
  // on another thread (or process, or machine)
  condition.notify();
```

The MySQLSleepBasedCondition is based on the MySQL ``SLEEP()`` and ``KILL QUERY``

The thread that is woken up is guaranteed to be the one that has waited the longest.


Queue
-----

A distributed MySQL backed Java BlockingQueue

```java
  DataSource ds = ...
  BlockingQueue<String> queue = new MySQLBasedQueue<String>(ds, "queue name", String.class);
  queue.add("Some String");
  
  // on another thread (or process, or machine)
  String s = queue.poll(); // Non blocking
  // or
  String s = queue.take(); // Blocks until element available
```

The MySQLBasedQueue uses the MySQLSleepBasedCondition to help form a blocking
queue, that can work without polling the database for new work.


Build and Release
-----------------

To build this project use `mvn`.

To push a release to maven central use the standard maven release plugin, and Sonatype's OSS repo:

```bash
mvn release:prepare
mvn release:perform
```

Useful Articles
---------------
	https://blog.engineyard.com/2011/5-subtle-ways-youre-using-mysql-as-a-queue-and-why-itll-bite-you