Protecting information in databases and possibility to restore databases in case of need is the highest priority task in many companies. But not all DBMSs have built-in tools for data protection (tools to backup and restore databases). And MySQL is one of such DBMSs.

Making database backups is one of the most important things in the process of administrating MySQL databases, because some critical data loss can be irreplaceable.

The task of making daily mysql backup can be solved with the help of the backup database function of dbForge Studio for MySQL. To use it, you should setup backup in the wizard manually and schedule making backups.

To open the Database Backup wizard, you should choose Database → Backup Database from the main menu. …

Connector/J has long provided an effective means to distribute read/write load across multiple MySQL server instances for Cluster or master-master replication deployments, but until version 5.1.13, managing such deployments frequently required a service outage to redeploy a new configuration.  Given that ease of scaling out by adding additional MySQL Cluster (server) instances is a key element in that product offering, which is also naturally targeted at deployments with very strict availability requirements, we had to add support for online changes of this nature.  It’s also critical for online upgrades – the other option is to take a MySQL Cluster server instance down hard, which loses any in-process transactions and generates application exceptions, if any application is trying to use that particular server instance.

Mark Matthews and I first …

In a previous blog post, I wrote about Connector/J’s failover policies, I described three triggers which cause Connector/J to re-balance (potentially selecting a new physical connection to another host):

1. At transaction boundaries (transactions are explicitly committed or rolled back)
2. A communication exception (SQL State starting with “08″) is encountered
3. When a SQLException matches conditions defined by user, using the extension points defined by the loadBalanceSQLStateFailover, loadBalanceSQLExceptionSubclassFailover or loadBalanceExceptionChecker properties.

Those conditions fit most needs very well, but there are situations where people are running with auto-commit enabled (no explicit transaction commit or rollback), and the end result is that Connector/J never …

In posts on June 30 and July 6, we explained how implementing the commands “replace into” and “insert ignore” with TokuDB’s fractal trees data structures can be two orders of magnitude faster than implementing them with B-trees. Towards the end of each post, we hinted at that there are some caveats that complicate the story a little. In this post, we explain one of the complications: the calculation of affected rows.

MySQL returns the number of rows affected by a “replace” or “insert” statement to the client. For the “replace” statement, the number of affected rows is defined to be the sum of the number of rows …

I was asked to write a blog post about MySQL High Availability at Yahoo, particularly for writes. Our standard practice is not particularly high-tech, but we've been using it for over 4 years now and it has become a company-wide standard with a few exceptions.   Let me start by saying that at Yahoo! we consider a datacenter as a Single Point of Failure (SPoF). We build and manage many of our own datacenters, and we still don't assume they are invulnerable. How many people can attest to the fact that however to configure your racks, how many redundant switches, power supplies, drives, etc. you buy, if your leased datacenter has power or network issues, you are at their mercy.  

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I have started seriously using PHP 5.3 recently due to it finally making it into Portage. (Gentoo really isn't full of bleeding edge packages people.) I have used mysqlnd a little here and there in the past, but until it was really coming to my servers I did not put too much time into it.

What is mysqlnd?

mysqlnd is short for MySQL Native Driver. In short, it is a driver for MySQL for PHP that uses internal functions of the PHP engine rather than using the externally linked libmysqlclient that has been used in the past. There are two reasons for this. The first reason is licensing. MySQL is a GPL project. The GPL and the PHP License don't play well together. The second is better memory management and hopefully more performance. Being a performance junky, this is what peaked my interests. Enabling mysqlnd means it is used by the older MySQL extension, the newer MySQLi extension and the MySQL PDO …

In this chapter we discuss timeouts which can lead to "MySQL server has gone away" and "Lost connection to MySQL server" errors.

 Extract here is short, because there are a lot of code quotes which I can not properly format here.

Chapter 9. Misterious vanishing of the server.

Often this looks like:


$php phpconf2009_3.php

string(26) "MySQL server has gone away"


Code:

...

Rest of the chapter is here

OUTER JOIN queries in SQL are susceptible to two very subtle bugs that I’ve observed a number of times in the real world. Daniel and I have been hammering out ways to automatically detect queries that suffer from these bugs, in a relatively new Maatkit tool called mk-query-advisor. It’s part of our series of advisor tools for MySQL. I wrote a blog post about it a while ago. Automated analysis of bad query patterns is a good thing to write tools to do, because catching buggy queries is hard work if you do it manually.

Let’s dive right in and analyze these subtle bugs. Warning: if you don’t understand how SQL handles NULL, you’re not going to understand the following. Many people have a hard time with NULL, which is why these bugs are so hard to …

In this chapter we discuss timeouts which can lead to "MySQL server has gone away" and "Lost connection to MySQL server" errors.

 Extract here is short, because there are a lot of code quotes which I can not properly format here.

Chapter 9. Misterious vanishing of the server.

Often this looks like:


$php phpconf2009_3.php

string(26) "MySQL server has gone away"


Code:

...

Rest of the chapter is here

As olap4j heads towards release 1.0, there are further signs that it is coming of age, in the form of drivers for the Palo MOLAP engine and SAP BW.

A few days ago Paul Stoellberger announced that olap4j's XMLA driver could connect to SAP BW, and posted pictures of PAT, PRD and PDI to prove it.

And just a week later, Jedox CEO Kristian Raue writes about how to connect to Palo. His post includes a blessedly short Java program …