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Showing entries 1 to 10 of 34418 10 Older Entries
Optimizer Trace and EXPLAIN FORMAT=JSON in 5.7
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I accidentally stumbled upon this Stack Overflow question this morning:

I am wondering if there is any difference in regards to performance between the following:

SELECT ... FROM ... WHERE someFIELD IN(1,2,3,4);
SELECT ... FROM ... WHERE someFIELD between  0 AND 5;
SELECT ... FROM ... WHERE someFIELD = 1 OR someFIELD = 2 OR someFIELD = 3 ...;

It is an interesting question because there was no good way to answer it when it was asked in 2009. All of the queries resolve to the same output in EXPLAIN. Here is an example using the …

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History Repeats: MySQL, MongoDB, Percona, and Open Source
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History is repeating again. MongoDB is breaking out of the niche into the mainstream, performance and instrumentation are terrible in specific cases, MongoDB isn’t able to fix all the problems alone, and an ecosystem is growing.

This should really be a series of blog posts, because there’s a book’s worth of things happening, but I’ll summarize instead. Randomly ordered:

  • MongoDB is in many respects closely following MySQL’s development, 10 years offset. Single index per query, MyISAM-like storage engine, etc. …
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Optimizing Out-of-order Parallel Replication with MariaDB 10.0
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Fri, 2015-05-22 07:19geoff_montee_g

Out-of-order parallel replication is a great feature in MariaDB 10.0 that improves replication performance by committing independent transactions in parallel on a slave. If slave_parallel_threads is greater than 0, then the SQL thread will instruct multiple worker threads to concurrently apply transactions with different …

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Introducing MySQL Performance Analyzer
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At Yahoo, we manage a massive number of MySQL databases spread across multiple data centers. 

In order to identify and respond to performance issues, we rely on an extremely lightweight and robust web based tool to proactively investigate the issues in them.

The tool has real time tracking features and continually gathers the most important performance metrics, provides visualization and statistical analysis for quickly identifying performance patterns, bottlenecks and possible tuning opportunities.


  • Lightweight Agentless Java Web Application
  • Rich User Interface
  • Gather and Store …

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Decrypt .mylogin.cnf
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General-purpose MySQL applications should read MySQL option files like /etc/my.cnf, ~/.my.cnf, ... and ~/.mylogin.cnf. But ~/.mylogin.cnf is encrypted. That's a problem for our ocelotgui GUI application, and I suppose other writers of Linux applications could face the same problem, so I'll share the code we'll use to solve it.

First some words of defence. I think that encryption (or more correctly obfuscation) is okay as an option: a customer asked for it, …

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Creating and Restoring Database Backups With mysqldump and MySQL Enterprise Backup – Part 2 of 2
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In part one of this post, I gave you a couple examples of how to backup your MySQL databases using mysqldump. In part two, I will show you how to use the MySQL Enterprise Backup (MEB) to create a full and partial backup.

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Bash Arrays & Oracle
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Last week, I wrote about how to use bash arrays and the MySQL database to create unit and integration test scripts. While the MySQL example was nice for some users, there were some others who wanted me to show how to write bash shell scripts for Oracle unit and integration testing. That’s what this blog post does.

If you don’t know much about bash shell, you should start with the prior post to learn about bash arrays, if-statements, and for-loops. In this blog post I only cover how to implement a bash

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Updates To Our Fault Detection Algorithm
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Unexpected downtime is one of your worst nightmares, but most attempts to find problems before they happen are threshold-based. Thresholds create noise, and alerts create false positives so often you may miss actual problems.

When we began building VividCortex, we introduced Adaptive Fault Detection, a feature to detect problems through a combination of statistical anomaly detection and queueing theory. It’s our patent-pending technique to detect system stalls in the database and disk. These are early indicators of serious problems, so it’s really helpful to find them. (Note: “fault” is kind of an ambiguous term for some people. In …

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Log Buffer #423: A Carnival of the Vanities for DBAs
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This Log Buffer edition covers Oracle, SQL Server and MySQL blog posts from all over the blogosphere!


Hey DBAs:  You know you can  install and run Oracle Database 12c on different platforms, but if you install it on an Oracle Solaris 11 zone, you can take additional advantages.

Here is a video with Oracle VP of Global Hardware Systems Harish Venkat talking with …

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Percona XtraBackup 2.3.1-beta1 is now available
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Percona is glad to announce the release of Percona XtraBackup 2.3.1-beta1 on May 20th 2015. Downloads are available from our download site here. This BETA release, will be available in Debian

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Showing entries 1 to 10 of 34418 10 Older Entries

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