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Displaying posts with tag: Tools (reset)
when xtrabackup fails with 'read' returned OS error 0 after upgrading to 5.7

Here's something that has puzzled me for several weeks.
Right after migrating  MySQL from 5.6 to 5.7, we started experiencing random xtrabackup failures on some, but not all, of our slaves.
The failures were only happening when taking an incremental backup, and it would always fail on the same table on each slave, with errors similar to the following:

171106 13:00:33 [01] Streaming ./gls/C_GLS_IDS_AUX.ibd
InnoDB: 262144 bytes should have been read. Only 114688 bytes read. Retrying for the remaining bytes.
InnoDB: 262144 bytes should have been read. Only 114688 bytes read. Retrying for the remaining bytes.
InnoDB: 262144 bytes should have been read. Only 114688 bytes read. Retrying for the remaining bytes.
InnoDB: 262144 bytes should have been read. Only 114688 bytes read. Retrying for the remaining bytes.
InnoDB: 262144 bytes should have been read. Only 114688 bytes read. Retrying for …

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Protocol reverse engineering with tcpdump

Sometimes network protocols don’t entirely behave as documented. Other times there is no documentation at all beyond code. Either way you can sometimes find a need to sniff the traffic of a connection to find out what is really going on.

Whilst I have been working on MariaDB ColumnStore for a year now there are still some parts of the codebase I know little about. I recently had to write some code that worked with the network protocol of ColumnStore, but there were a few parts that were difficult to understand exactly what was happening just by looking at the code. This is where tcpdump came in.

tcpdump is a powerful tool to help you sniff the raw packet data for network connections. It can be very verbose giving parts of the TCP/IP handshake, headers, etc… This is way more than I often need …

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What does pt-show-grants look like?

[note: A broken link from a defunct blog made me dig up this post from archive.org and re-post it here; Beginners may find this informative!]

The OurSQL Podcast did an episode on some of the lesser-known but very useful tools in the Percona Toolkit. pt-show-grants is one of those tools that I use pretty frequently. While the manual page has an explanation of all the features and a few examples, you dont really see the output, and often you decide whether or not to use a tool based on what it gives you as output.

So here is a small example of an actual command I did today using pt-show-grants. I wanted to find the grants for a particular user. To do …

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Evaluation of PMP Profiling Tools

In this blog post, we’ll look at some of the available PMP profiling tools.

While debugging or analyzing issues with Percona Server for MySQL, we often need a quick understanding of what’s happening on the server. Percona experts frequently use the pt-pmp tool from Percona Toolkit (inspired by http://poormansprofiler.org).

The

pt-pmp

 tool collects application stack traces GDB and then post-processes them. From this you get a condensed, ordered list of the stack traces. The list helps you understand where the application spent most of the time: either running something or waiting for something.

Getting a profile with

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Generating a MySQL Password

One of the services our database engineers provide is adding users to MySQL. We have some nice Chef recipes, so all I have to do is update a few files, including adding in the MySQL password hash.

Now, when I added myself, I just logged into MySQL and generated a password hash. But when my SRE (systems reliability engineer) colleague needed to generate a password, he did not have a MySQL system he could login to.

The good news is it’s easy to generate a MySQL password hash. The MySQL password hash is simply a SHA1 hash of a SHA1 hash, with * at the beginning. Which means you do not need a MySQL database to create a MySQL password hash – all you need is a programming language that has a SHA1 function (well, and a concatenate function).

And I found it, of course, on this post at StackExchange (http://unix.stackexchange.com/a/234592/217471). So you don’t have to click through, here is what it says – and I have …

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PyMyTools: Simple diagnostic tools for Amazon Aurora and MySQL

This post introduces PyMyTools v0.1: my first version of a simple diagnostic toolkit for automating boring DBA tasks. Read on for tool descriptions and demonstrations!

Introduction No lengthy introductions this time:

  • I wrote these tools to make my own everyday tasks less time consuming. I hope you too will find them useful.
  • Tools can be downloaded from GitHub and are provided under the MIT License.
  • Your feedback is very welcome (use GitHub Issues).

Tools: general description The tools are designed to automate some of the simple DBA tasks:

  • Monitor the values of server status variables.
  • Report on basic status variables (buffer/cache usage, uptime, query traffic).
  • Dump …
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Introducing BakaSQL, the MySQL web-based sandbox for query execution

BakaSQL: a bit of history When I joined this new company I was already aware there was a lot of work to do. There was no DBA Team to speak of; any MySQL related task was handled by the sysadmins, and the company was growing as fast as you can imagine, with 15-20 new employees arriving each month, most of them in the IT department. For sure, there was much fun ahead.

During my first week in the new job  I immediately felt that something was not right. I was receiving too much DMLs to execute each day, spanning a wide set of servers, schemas an tables. This is not something I had seen before, so I started asking around what the reason behind it was.  It turned out that there were multiple reasons behind it:

  • there were known bugs in the applications that were never fixed
  • application configuration items were stored in MySQL, but there was no admin panel to modify them
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New tool: GitHub's online schema migration for MySQL

Shlomi Noach from the the Github engineering team posted the release of a new tool for triggerless online schema migration with MySQL. Although it's mostly targeted at databases using a replication architecture, if you don’t have replicas, or do not wish to use them, you are still able to operate directly on the master. In spite of being a wonderful project and being used in production by

Introducing gh-ost: triggerless online schema migrations

I'm thoroughly happy to introduce gh-ost: triggerless, controllable, auditable, testable, trusted online schema change tool released today by GitHub.

gh-ost now powers our production schema migrations. We hit some serious limitations using pt-online-schema-change on our large volume, high traffic tables, to the effect of driving our database to a near grinding halt or even to the extent of causing outages. With gh-ost, we are now able to migrate our busiest tables at any time, peak hours and heavy workloads included, without causing impact to our service.

gh-ost supports testing in production. It goes a long …

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Developing a MySQL Workbench plugin

The MySQL Workbench tool is great for development and administration tasks. Also it's available on Windows, Linux and Mac OS X which, according to information from third party sources, is more than you can say for most of the other equivalent tools. And Workbench is free. Having said that, most of the provided functionalities are intuitive and of daily use for developer and DBA staff alike.

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