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Displaying posts with tag: MySQL (reset)
Virtual columns in MySQL and MariaDB

In this blog post, we’ll compare virtual columns in MySQL and MariaDB.

Virtual columns are one of my top features in MySQL 5.7: they can store a value that is derived from one or several other fields in the same table in a new field. It’s a very good way to build a functional index. This feature has been available in MariaDB for some time, so let’s compare the two and see if they are equivalent. We’ll look at different aspects for this comparison.

Documentation

The MariaDB documentation is very easy to find.

Finding the documentation for virtual columns in 5.7 is a bit more challenging. …

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Percona Server 5.5.48-37.8 is now available


Percona is glad to announce the release of Percona Server 5.5.48-37.8 on March 4, 2016. Based on MySQL 5.5.48, including all the bug fixes in it, Percona Server 5.5.48-37.8 is now the current stable release in the 5.5 series.

Percona Server is open-source and free. Details of the release can be found in the 5.5.48-37.8 milestone on Launchpad. Downloads are available here and from the …

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2016 Annual Pythian MySQL Community Dinner

Once again, Pythian is organizing an event that by now may be considered a tradition: The MySQL community dinner at Pedro’s! This dinner is open to all MySQL community members since many of you will be in town for Percona Live that week. Here are the details:

What: The MySQL Community Dinner

When: Tuesday April 19, 2016 –  7:00 PM at Pedro’s (You are welcome to show up later, too!)

Where: Pedro’s Restaurant and Cantina – 3935 Freedom Circle, Santa Clara, CA 95054

Cost: Tickets are $40 USD, Includes Mexican buffet, non-alcoholic drinks, taxes, and gratuities (see menu)

How: Purchase your ticket below …

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GROUP BY, are you sure you know it?

New MySQL version, YAY!

MySQL 5.7 is full of new features, like virtual columns, virtual indexes and JSON fields! But, it came with some changes to the default configuration. When running:

SELECT @@GLOBAL.sql_mode;

We get:

ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

What I want to talk about is the ONLY_FULL_GROUP_BY mode. This mode rejects queries where nonaggregated columns are expected, but aren’t on the GROUP BY or HAVING clause. Before MySQL 5.7.5, ONLY_FULL_GROUP_BY was disabled by default, now it is enabled.

You know the drill…

This is a simple statement, people use it everywhere, it shouldn’t be that hard to use, right?

Given the following schema:

Suppose I want to list all users that commented on …

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MySQL on FreeBSD: old genes

Maintaining mission critical databases on our pitchfork wielding brother, the “Daemon” of FreeBSD, seems quite daunting, or even absurd, from the perspective of a die-hard Linux expert, or from someone who has not touched it in a long time. The question we ask when we see FreeBSD these days is “why?”.  Most of my own experience with FreeBSD was obtained 10-15 years ago.  Back then, in the view of the team I was working on, a custom compiled-from-source operating system like FreeBSD 5.x or 6.x was superior to a Linux binary release.

Package managers like YUM and APT were not as good.  They did not always perform MD5 checks and use SSL like today’s versions. RedHat wasn’t releasing security updates 5 minutes after a vulnerability was discovered. Ubuntu didn’t exist. Debian stable would get so very old before receiving a new version upgrade. FreeBSD was a great choice for a maintainable, secure, free open …

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Eating our own dog food – Running JIRA on MariaDB

A couple of weeks ago we announced that we were moving from a hosted instance of JIRA to our self hosted instance. The main reason was that we hit 2000 active users in the hosted instance of JIRA and that is the upper limit that it  supports. We obviously wanted to allow more people to […]

The post Eating our own dog food – Running JIRA on MariaDB appeared first on MariaDB.org.

Sometimes a Variety of Databases is THE Database You Need

We were just leafing through the 2015 edition of The DZone Guide to Database and Persistence Management, and we noticed some interesting stats in the guide's included survey, about which we'd like to share some observations. The survey is one of the ebook's central features, and it includes feedback from over 800 IT Professionals, with 63% of those respondents coming from companies with over 100 employees and 69% with over 10 years of experience -- they represent a significant and important cross-section of our industry.

These kinds of reports can be enlightening, as they offer the opportunity to take some of our principles and pin them to the hard facts and numbers of actual database activity, in the field. 

In a section titled "One Type of Database is Usually Not Enough," the report reveals that it's stadard …

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SQL Injection with MySQL SLEEP()

Recently we’ve received an alert from one of our clients that running threads are high on one of their servers. Once we logged in, we noticed that all the selects were waiting for table level read lock. We scrolled through the process list, and found the selects which were causing the problems. After killing it, everything went back to normal.
At first we couldn’t understand why the query took so long, as it looked like all the others. Then we noticed, that one of the WHERE clauses was strange. There, we found a SLEEP(3) attached with OR to the query. Obviously, this server was the victim of a SQL injection attack.

What is SQL injection?

I think most of us know what SQL injection is, but as a refresher, SQL injection is when someone provides malicious input into WHERE, to run their own statements as well.
Typically this occurs when you ask a user for input, like username, but instead of a real name they give you a …

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Taking the new MySQL 5.7 JSON features for a test drive

MySQL 5.7 introduces both a new native JSON datatype, and a set of SQL functions to be able to manipulate and search data in a very natural way on the server-side. Today I wanted to show a simple of example of these features in action using sample data from SF OpenData.…

How MaxScale monitors servers

In this post, we’ll address how MaxScale monitors servers. We saw in the

We saw in the previous post how we could deal with high availability (HA) and read-write split using MaxScale.

If you remember from the previous post, we used this section to monitor replication:

[Replication Monitor]
type=monitor
module=mysqlmon
servers=percona1, percona2, percona3
user=maxscale
passwd=264D375EC77998F13F4D0EC739AABAD4
monitor_interval=1000
script=/usr/local/bin/failover.sh
events=master_down

But what are we monitoring? We are monitoring the assignment of master and slave roles inside MaxScale according to the actual replication tree in the cluster using the …

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