In this blog post, we are going to show you some examples of things that can go wrong in Galera - inexplicable node crashes, network splits, clusters that won’t restart and inconsistent data. We’ll take a look at the data stored in log files to diagnose the problems, and discuss how we can deal with these.

This builds upon the previous post, where we looked into log files produced by Galera (error log and innobackup.* logs). We discussed how regular, “normal” activity looks like - from initialization of Galera replication to Incremental State Transfer (IST) and State Snapshot Transfer (SST) processes, and the respective log entries. 

This is the seventeenth installment in the ‘Become a MySQL DBA’ blog series. Our previous posts in the DBA series include:

• …

With MySQL, it is relatively easy to create “point in time” restores. All you need is recent(ish) backup and a bunch of saved binary logs. You can restore the backup you have, and when it is completed, you can use mysqlbinlog utility to apply your saved binary logs to the desired state of your database.

I have created a simple go application to make your life easier. You can find it on my GitHub page.

The app works as reading its config file for the MySQL server connection credentials, a local directory where the binary logs will be kept, and the will path of the mysqlbinlog utility.

1. It checks the binlogs on the remote server which able to streamed
2. Checks the local directory where the binlogs are kept, to check which logs are already there
3. The incomplete (file size differs local and on remote server) files will be …

Recently my colleague (by Percona) Yves Trudeau and colleague (by industry) Marco Tusa
published their materials on Amazon Aurora. Indeed, Amazon Aurora is a hot topic these days, and we have a stream of customer inquiries regarding this technology. I’ve decided to form my own opinion, and nothing is better than a personal, hands-on experience, which I am going to share.

The materials I will refer to:

• [1] Presentation from Amazon Re:Invent: …

ScaleDB 15.10 is out. Some users have downloaded it and tested it and we have received pretty positive feedback, but also some requests to have more info and help on how to start. I will try to condense here the basic steps to install and test ScaleDB ONE for the first time.
First of all, some terminology. We have two versions: ScaleDB ONE and ScaleDB Cluster. ScaleDB ONE is meant to be used on a single machine (ONE = One Node Edition), whether it is a VM, a cloud instance or a physical server, whilst ScaleDB Cluster is the full size, multi-node cluster that everybody expects to run for mission critical applications. This means that the typical use cases for ScaleDB ONE are testing and development, data marts and streaming data collection and analysis that are limited by a single server (although you can always replicate your data to another server using the standard MySQL Replication). ScaleDB Cluster instead, is highly …

With MySQL it is relatively easy to create point in time restores. All you need is a recent(ish) backup, and a bunch of saved binary logs. You can restore the backup you have, and when it is completed, you can use mysqlbinlog utility to apply your saved binary logs to the desired state of your database. I […]

We are very pleased to announce that the MySQL Connector/Net source code has been added to GitHub. All of our versions can be found at MySQL Connector/Net repository, under the umbrella of the MySQL organization. This repository will expose the source code of the latest generally available (GA) releases. Same versions that are available in the official MySQL download site.

There are no changes to the releases cycles or the channels that we use for publishing new versions of Connector/Net. The purpose of publishing on GitHub is providing our users a quicker way to get the source code of all our GA versions. The repository contains all history since 6.7 alpha version.

Previous episodes:

• MySQL-Docker operations. - Part 1: Getting started with MySQL in Docker.
• MySQL-Docker operations. - Part 2: Customizing MySQL in Docker.
• MySQL-Docker operations. - Part 3: MySQL replication in Docker.

We're going to explore the choices and the differences between various types of deployments. We will consider four use cases:

1. [Friendly]: Testing an application on a server where a different version of the same application is already installed (examples: a Python app requiring many …

Summary from last blog:

• Tip: An alias for Get-CimInstance is GCim, for Select-Object it's Select and for Get-WmiObject is GWmi.
• There are Raw and Formatted counters. Watch out for formula converting Raw samples to Formatted values.

NAMESPACE organizationThe general organization of namespaces is as follows:
  Category (Class if you prefer)
    Counter(s)
      Instance(s)
Every Category has Counters but not all of the Counters have Instances. The full path to the desired value is called a __PATH:

PS > GWmi Win32_PerfFormattedData_PerfOS_Processor | Select __Path

__PATH
------
      namespace …

You have created a large database with thousands of tables (> 5000 in MySQL 5.6). Then you want to create a backup using xtrabackup. Or, if it is a Galera cluster, you have to recover a galera node using wsrep_sst_method=xtrabackup[-v2].

Unfortunately it fails and the following is emitted in the Job Logs messages:

xtrabackup: Generating a list of tablespaces
2015-11-03 19:36:02 7fdef130a780  InnoDB: Operating system error number 24 in a file operation.
InnoDB: Error number 24 means 'Too many open files'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/operating-system-error-codes.html
InnoDB: Error: could not open single-table tablespace file ./DB75/t69.ibd

In this case you can simply increase the open_files_limit of the MySQL server(s) by going to Manage > Configurations, click on Change Parameter.

…

Requires ClusterControl 1.2.11 or later. Applies to MySQL single instances, replications and Galera clusters.

You have created a large database with thousands of tables (> 5000 in MySQL 5.6). Then you want to create a backup using xtrabackup. Or, if it is a Galera cluster, you have to recover a galera node using wsrep_sst_method=xtrabackup[-v2].

Unfortunately it fails and the following is emitted in the Job Logs messages:

xtrabackup: Generating a list of tablespaces
2015-11-03 19:36:02 7fdef130a780  InnoDB: Operating system error number 24 in a file operation.
InnoDB: Error number 24 means 'Too many open files'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/operating-system-error-codes.html
InnoDB: Error: could not open single-table tablespace file ./DB75/t69.ibd

In this case …