My server is crashing… Now what?

This special episode in the MySQL QA Series is for customers or users experiencing a crash.

1. A crash?
   1. Cheat sheet: https://goo.gl/rrmB9i
   2. Sever install & crash. Note this is as a demonstration: do not action this on a production server!
      sudo yum install -y http://www.percona.com/downloads/percona-release/redhat/0.1-3/percona-release-0.1-3.noarch.rpm
      sudo yum install -y Percona-Server-client-56 Percona-Server-server-56
      sudo service mysql start
2. Gimme Stacks!
   1. Debug info packages (can be executed on a production system, but do match your 5.5, 5.6 or 5.7 version correctly)
      sudo yum install -y Percona-Server-56-debuginfo
   …

Today’s episode is all about Valgrind – from the pro’s to the con’s, from the why to the how! This episode will be of interest to anyone who is or wants to work with Valgrind on a regular or semi-regular basis.

1. Pro’s/Why
2. Con’s
3. How
   1. Using the latest version
      sudo [yum/apt-get] install valgrind
      #OR#
      sudo [yum/apt-get] remove valgrind
      sudo [yum/apt-get] install bzip2 glibc*
      wget http://valgrind.org/downloads/valgrind-3.10.1.tar.bz2
      tar -xf valgrind-3.10.1.tar.bz2; cd valgrind-3.10.1
      ./configure; make; sudo make install
      valgrind –version # This should now read 3.10.1
   2. VGDB (cd ./mysql-test)
      ./lib/v1/mysql-test-run.pl –start-and-exit –valgrind –valgrind-option=”–leak-check=yes”
      –valgrind-option=”–vgdb=yes” …

Welcome to the 10th episode in the MySQL QA series! Today we’ll talk about reproducing and simplifying: How to get it Right.

Note that unless you are a QA engineer stuck on a remote, and additionally difficult-to-reproduce or difficult-to-reduce bug, this episode will largely be non-interesting for you.

However, what you may like to see – especially if you watched episodes 7 (and possibly 8 and 9) – is how reducer automatically generates handy start/stop/client (cl) etc. scripts, all packed into a handy bug tarball, in combination with the reduced SQL testcase.

This somewhat separate part is covered directly after the introduction (ends at 11:17), as well as with an example towards the end of the video (starts at time index 30:35).

The “in between part” (11:17 to 30:35) is all about reproducing and simplifying, which – unless you are working on a remote case – can likely be skipped by …

Welcome to MySQL QA Episode 9. This episode will go more in-depth into reducer.sh: Reducing Testcases for Experts: multi-threaded reducer.sh

We will explore how to use reducer.sh to do true multi-threaded testcase reduction – a world’s first.

Topics:

1. Expert configurable variables & their default reducer.sh settings
   1. PQUERY_MULTI
   2. PQUERY_MULTI_THREADS
   3. PQUERY_MULTI_CLIENT_THREADS
   4. PQUERY_MULTI_QUERIES
   5. PQUERY_REVERSE_NOSHUFFLE_OPT

Full-screen viewing @ 720p resolution recommended.

The post MySQL QA Episode 9: Reducing Testcases for Experts: multi-threaded reducer.sh appeared first on …

Welcome to MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh

1. Advanced configurable variables & their default/vanilla reducer.sh settings
   1. FORCE_SKIPV
   2. FORCE_SPORADIC
   3. TIMEOUT_COMMAND & TIMEOUT_CHECK
   4. MULTI_THREADS
   5. MULTI_THREADS_INCREASE
   6. QUERYTIMEOUT
   7. STAGE1_LINES
   8. SKIPSTAGE
   9. FORCE_KILL
2. Some examples
   1. FORCE_SKIPV/FORCE_SPORADIC
   2. TIMEOUT_COMMAND/TIMEOUT_CHECK

Full-screen viewing @ 720p resolution recommended.

The post MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh …

Welcome to MySQL QA Episode #7 – Reducing Testcases for Beginners: single-threaded reducer.sh!

In this episode we’ll learn how to use reducer.sh. Topics discussed;

1. reducer.sh introduction/concepts
2. Basic configurable variables & their default reducer.sh settings
   1. INPUTFILE options
   2. MODE=x
   3. TEXT=”text”
   4. WORKDIR_LOCATION & WORKDIR_M3_DIRECTORY
   5. MYEXTRA
   6. MYBASE
   7. PQUERY_MOD & PQUERY_LOC
   8. MODE5_COUNTTEXT, MODE5_ADDITIONAL_TEXT & MODE5_ADDITIONAL_COUNTTEXT
   9. How to learn more about each of the settings
3. Manual example
4. Introduction to the script’s self-recursion concept – subreducer
5. Quick setup re-cap, details of an already executed QA run
6. Examples from …

Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies”

In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered:

1. GDB Introduction
2. Backtrace, Stack trace
3. Frames
4. Commands & Logging
5. Variables
6. Library dependencies
7. c++filt
8. Handy references
– GDB Cheat sheet (page #2): https://goo.gl/rrmB9i
– From Crash to testcase: https://goo.gl/3aSvVW

Also expands on live debugging & more. In HD quality (set your player to 720p!)

The post MySQL QA Episode 3: How to use the debugging tool GDB appeared first on …

Welcome to MySQL QA Episode 2: Build a MySQL Server – Git, Bazaar (bzr), Compiling, and Build Tools

In this episode you’ll learn how to build Percona Server and/or MySQL Server for QA purposes & more in this short 25 minute tutorial.

In HD quality (set your player to 720p!)

To watch the other episodes in this series, see the MySQL QA & Bash Linux Training Series post. If you missed MySQL QA Episode 1, it was titled “Bash/GNU Tools & Linux Upskill & Scripting Fun.” You are watch it here.

If you have any questions or comments, please leave them below.

The post …

After we released pquery to the community, and as we started logging bug reports with pquery testcases, it quickly became clear that pquery binaries with statically compiled-in client libraries would be of great convenience, both for ourselves and for the community.

(If you haven’t heard about pquery yet, read the pquery introduction blog post, come and join the pquery introduction lightning talk at Percona Live (15 April just around 6PM in Hall A), or keep an eye out for some of the upcoming episodes in the …

Two years ago Ovais Tariq had explained in detail what kinds of problems existed before MySQL introduced metadata locks in 5.5.3 and how these locks help to prevent them. Still, some implications of metadata locking in MySQL remain unclear for users – DBAs and even software developers that target recent MySQL versions. I’ve decided to include a slide or two into the presentation about InnoDB locks and deadlocks I plan to make (with my colleague Nilnandan Joshi) on April 16 at Percona Live 2015.

I decided to do this as …