Tag: speculations

Feed: Planet MySQL; Author: Valeriy Kravchuk; I've decided to stop reviewing MySQL Release Notes in this series, but it does not mean that I am not interested in MySQL bugs any more. At the moment I am subscribed to 91 active MySQL bugs reported by other MySQL users, and in this blog post I am going to present 15 of them, the most recently reported ones. I'd really want to see them fixed or at least properly processed as soon as possible.In some cases I am going to add my speculations on how the bug had better be handled, or ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. This is a "Howto" kind of post, and some speculations and historical references aside, it will show you how to build MariaDB ColumnStore (current version 1.0.9) from GitHub source, how to install and configure it for basic usage, as well as how to resolve some minor problems you may get in the process. Keep reading and eventually you'll get the real Howto below :) * * * I try not to care about any software issues besides good old MySQL, InnoDB storage engine internals, query optimization and some MyRocks or a little bit of ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. Back in January 2014, some time after many nice people kindly asked me to shut up stop writing about MySQL bugs on Facebook several times per day, I decided to start reading the fine MySQL Manual more carefully than before and report not only typos there, but also any topic or detail not properly explained. Usually these reports, tagged as "missing manual", were the result of careful study of the documentation based on real user question or customer issue. So, most of these reports came from real life, and missing information badly affected poor ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: NYC Data Science Academy. Contributed by Oamar Gianan. He enrolled in the NYC Data Science Academy 12-week full time Data Science Bootcamp program taking place between September 23, 2016 and December 23, 2016. The original article can be found here. Have you been followed on Twitter or Instagram by someone you don't know? I get this a lot. And so to avoid being thought of as rude, I follow back. Eventually, I got tired of following back when I realized that some of these accounts don't really do anything but collect followers. Now, why would anyone ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. It seems recent post on Group Replication by Vadim caused an interesting discussion on Facebook. I am NOT going to continue it here, but decided to present some facts, specifically, list of public bug reports and feature requests for Group Replication (mostly "Verified", that is, accepted by Oracle engineers as valid) as of MySQL 5.7.17 (where the feature is promoted as GA), with just few comments to some of the bugs.The goal is to double check this post when next Oracle MySQL 5.7.x release appears, to find out how much Oracle carews to fix ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. My previous post on MyRocks was intended to provide some background details for a couple of slides for my FOSDEM talk on profiling MySQL. The results and performance demonstrated by MyRocks vs InnoDB from MySQL 5.7.17 were not really important to show how perf helps to understand where the time was spent while executing of one specific query vs the other (with the same results, but different plan), but they still caused a lot of comments from people who care, so I decided to double check and clarify few more details.First of all, it ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. Almost a year ago I've got really interested in MyRocks and built MySQL from Facebook that provides it from source. Since that time I build it from fresh sources few times per week (as I've described in that post) and once in a while try to work with it and study some details or use cases. Today I'd like to discuss one of them that I've recently studied with perf profiler.This is not only because I am going to talk about applying profilers to all kinds and forks of MySQL at FOSDEM 2017 MySQL ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. Oprofile was widely used for MySQL profiling on Linux in the past. But since 2010 and 2.6.31 Linux kernels another profiler, perf, gets increasing popularity. It uses performance counters (CPU hardware registers that count hardware events such as instructions executed) subsystem in Linux. perf is capable of lightweight profiling. It is included in the Linux kernel, under tools/perf (so features available depends on kernel version), and is frequently updated and enhanced.So, probably perf is the future of profiling on Linux and it makes sense to discuss its basic usage for profiling MySQL servers. For ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. Users had to identify the reasons for MySQL performance problems somehow well before famous Performance Schema appeared in MySQL 5.5.3, and even before Domas invented his Poor Man's Profiler. Poor users had to use some OS-level tools, and among these tools the most important one was, probably, oprofile.oprofile is a system-wide statistical profiling tool for Linux available since 2001 and 2.4.x kernels. It was applied to MySQL for many years and allowed to find and explain many performance problems. We even have the --collect-oprofile option for pt-stalk tool, and it's a common knowledge that ... Read More

Feed: Planet MySQL. Author: Valeriy Kravchuk. It's time to summarize the year of 2016. As a kind of a weird summary, in this post I'd like to share a list of MySQL bug reports I've created in 2016 that are still remaining "Verified" today:Bug #79831 - "Unexpected error message on crash-safe slave with max_relay_log_size set". According to Umesh this is not repeatable with 5.7. The fact that I've reported the bug on January 4 probably means I was working at that time. I should not repeat this mistake again next year. Bug #80067 - "Index on BIT column is NOT ... Read More