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Performance Evaluation of SST Data Transfer: Without Encryption (Part 1)

In this blog, we’ll look at evaluating the performance of an SST data transfer without encryption.

A State Snapshot Transfer (SST) operation is an important part of Percona XtraDB Cluster. It’s used to provision the joining node with all the necessary data. There are three methods of SST operation available: mysqldump, rsync, xtrabackup. The most advanced one – xtrabackup – is the default method for SST in Percona XtraDB Cluster.

We decided to evaluate the current state of xtrabackup, focusing on the process of transferring data between the donor and joiner nodes tp find out if there is any room for improvements or optimizations.

Taking into account that the security of the network connections used for Percona XtraDB Cluster deployment is one of the most important factors that affects SST performance, we will evaluate SST operations in two setups: without network encryption, and in …

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Webinar Thursday 3/30: MyRocks Troubleshooting

Please join Percona’s Principal Technical Services Engineer Sveta Smirnova, and Senior Software Engineer George Lorch, MariaDB’s Query Optimizer Developer Sergei Petrunia and Facebook’s Database Engineer Yoshinori Matsunobu as they present MyRocks Troubleshooting on March 30, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7).

Register Now

MyRocks is an alternative storage engine designed for flash storage. It provides great write workload performance and space efficiency. Like any other powerful engine, it has its own specific configuration scenarios that require special troubleshooting solutions.

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MySQL Tutorial - Troubleshooting MySQL Replication Part 2

In the previous post, we discussed how to verify that MySQL Replication is in good shape. We also looked at some of the typical problems. In this post, we will have a look at some more issues that you might see when dealing with MySQL replication.

Missing or Duplicated Entries

This is something which should not happen, yet it happens very often - a situation in which an SQL statement executed on the master succeeds but the same statement executed on one of slaves fails. Main reason is slave drift - something (usually errant transactions but also other issues or bugs in the replication) causes the slave to differ from its master. For example, a row which existed on the master does not exist on a …

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Network attacks on MySQL, Part 4: SSL hostnames

In my previous blogs I told you to enable SSL/TLS and configure it to check the CA. So I followed my advice and did all that. Great!

So the --ssl-mode setting was used a few times as a solution. And it has a setting we didn't use yet: VERIFY_IDENTITY. In older MySQL versions you can use --ssl-verify-server-cert. Both turn on hostname verification.

The attack

Get any certificate which is trusted by the configured CA, this can for example be a certificate from a development machine. And use that with a man-in-the-middle proxy.

Then the client:

  1. Checks if SSL is uses (--ssl-mode=REQUIRED)
  2. Verify if the certificate is signed by a trusted CA (--ssl-mode=VERIFY_CA)

Both checks succeed. But the certificate might be for and the database server might be …

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Troubleshooting Issues with MySQL Character Sets Q & A

In this blog, I will provide answers to the Q & A for the Troubleshooting Issues with MySQL Character Sets webinar.

First, I want to thank everybody for attending the March 9 MySQL character sets troubleshooting webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with responses:

Q: We’ve had some issues converting tables from




. Our issue was that the collation we wanted to use –

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MySQL 8.0 Collations: The devil is in the details.

One of the challenges of language specific collations, is making sure they are accurate in the edge-cases of sometimes lesser-used language features. Since I am Norwegian, let me use the Danish collation (which is identical to Norwegian collation) as an example:

Most Scandinavian people know that in Danish (and Norwegian), we have three extra letters: ‘Æ’, ‘Ø’ and ‘Å’ and they follow after ‘Z’ in that order.…

MySQL Tutorial - Troubleshooting MySQL Replication Part 1

Replication is one of the most common ways to achieve high availability for MySQL and MariaDB. It has become much more robust with the addition of GTIDs, and is thoroughly tested by thousands and thousands of users. MySQL Replication is not a ‘set and forget’ property though, it needs to be monitored for potential issues and maintained so it stays in good shape.  In this blog post, we’d like to share some tips and tricks on how to maintain, troubleshoot and fix issues with MySQL replication.

How to determine if MySQL replication is in a good shape?

This is hands down the most important skill that anyone taking care of a MySQL replication setup has to possess. Let’s take a look at where to look for information about the state of replication. There is a slight difference between MySQL and MariaDB and we will discuss this as well. …

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Howto Encrypt MySQL Backups on S3

TwinDB Backup supports encrypted backup copies since version 2.11.0. As usual the tool supports natively backup and restore operations, if backup copies are encrypted the tool takes care of decryption.

Installing TwinDB Packages repository

I will work with CentOS 7 system to show the example, but there are also packages for Ubuntu trusty and Debian jessie.

We host our packages in PackageCloud which provides a great installation guide if you need to install the repo via puppet, chef etc. The manual way is pretty straightforward as well. A PackageCloud script installs and configures the repository.

curl -s | sudo bash

Installing twindb-backup

Once the repository is ready it’s time to install the tool.

yum install …
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What’s Next for SQL Databases?

In this blog, I’ll go over my thoughts on what we can expect in the world of SQL databases.

After reading Baron’s prediction on databases, here:

I want to provide my own view on what’s coming up next for SQL databases. I think we live in interesting times, when we can see the beginning of the next-generation of RDBMSs.

There are defining characteristics of such databases:

  1. Auto-scaling. The ability to add and use resources depending on the current load and database size. This is done transparently for users and DBAs.
  2. Auto-healing. The automatic handling of node …
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Test a Flask App with Selenium WebDriver – Part 2

This is the second and final part of a tutorial on how to test a Python/Flask web app with Selenium webdriver. We are testing Project Dream Team, an existing CRUD web app. Part One introduced Selenium WebDriver as a web browser automation tool for browser-based tests. By the end of Part One, we had written tests for registration, login, performing CRUD operations on departments and roles, as well as assigning departments and roles to employees.

In Part Two, we will write tests to ensure that protected pages can only be accessed by authorised users. We will also integrate our app with CircleCI, a continuous integration and delivery platform. I have included a demo video showing all the tests running, so be sure to check it out!

Permissions …

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