In Amazon space, any EC2 or Service instance can “disappear” at any time.  Depending on which service is affected, the service will be automatically restarted.  In EC2 you can choose whether an interrupted instance will be restarted, or left shutdown.

For an Aurora instance, an interrupted instance is always restarted. Makes sense.

The restart timing, and other consequences during the process, are noted in our post on Aurora Failovers.

Aurora Testing Limitations

As mentioned earlier, we love testing “uncontrolled” failovers.  That is, we want to be able to pull any plug on any service, and see that the environment as a whole continues to do its job.  We can’t do that with Aurora, because we can’t control the essentials:

• power button;
• reset switch;
…

This is part-4 of the Maxscale Blog series

1. Maxscale and Galera
2. Maxscale Basic Administration
3. Maxscale for Replication

Maxscale started supporting Amazon Aurora lately from its version 2.1 which comes with a BSL license, we are good until we use only 3 nodes, …

In this blog post, I’ll look at how to make Percona XtraDB Cluster and SELinux work when used together.

Recently, I encountered an issue with Percona XtraDB Cluster startup. We tried to setup a three-node cluster using Percona XtraDB Cluster with a Vagrant CentOS box, but somehow node2 was not starting. I did not get enough information to debug the issue in the donor/joiner error log. I got only the following error message:

2018-02-08 16:58:48 7910 [Note] WSREP: Running: 'wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.100.20' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix '' --parent '7910' --binlog 'mysql-bin' '
2018-02-08 16:58:48 7910 [ERROR] WSREP: Failed to …

The conference session schedule for the seventh annual Percona Live 2018 Open Source Database Conference, taking place April 23-25 at the Santa Clara Convention Center in Santa Clara, CA is now live and available for review! Advance Registration Discounts can be purchased through March 4, 2018, 11:30 p.m. PST.

Percona Live Open Source Database Conference 2018 is the premier open source database event. With a theme of “Championing Open Source Databases,” the conference will feature multiple tracks, including MySQL, MongoDB, Cloud, PostgreSQL, Containers and Automation, Monitoring and Ops, and Database Security. Once again, Percona will be …

How it happened

A few years ago I started thinking about refactoring MySQL-Sandbox. I got lots of ideas and a name for the project (dbdeployer) but went no further. The initial idea (this was 2013!) was to rewrite the project in Ruby: I had been using Ruby at work and it looked like a decent replacement for Perl. My main problem was the difficulty of installation in an uncontrolled environment. If you have control over your environment (it's your laptop or you are in charge of the server configuration via Puppet or similar) then the task is easy. But if you ever need to deploy somewhere with little or no notice, it becomes a problem: there are servers where Perl is not installed, and is common that the server also have a policy forbidding all scripting languages from being deployed. …

Right now Aurora only allows a single master, with up to 15 read-only replicas.

Master/Replica Failover

We love testing failure scenarios, however our options for such tests with Aurora are limited (we might get back to that later).  Anyhow, we told the system, through the RDS Aurora dashboard, to do a failover. These were our observations:

Role Change Method

Both master and replica instances are actually restarted (the MySQL uptime resets to 0).

This is quite unusual these days, we can do a fully controlled role change in classic asynchronous replication without a restart (CHANGE MASTER TO …), and Galera doesn’t have read/write roles as such (all instances are technically writers) so it doesn’t need role changes at all.

Failover Timing

Failover between running instances takes about 30 seconds.  This is in line with information provided in the …

In this blog post, I will look at the new dashboards in Percona Monitoring and Management (PMM) for Prometheus exporters.

Percona Monitoring and Management (PMM) uses Prometheus exporters to capture metrics data from the system it monitors. Those Prometheus exporters are an important part of your monitoring infrastructure, and understanding their performance and other operational details is critical for well-implemented monitoring.    

To help you with this we’ve added a number of new dashboards to Percona Monitoring and Management.

The Prometheus Exporters Overview dashboard provides a high-level overview of your installed Prometheus exporter …

Or Fun in using MySQL8 with ProxySQL and MysqlJ connector

I am recently working on testing MySQL8 and try the several solution attach to it,like ProxySQL but not only.

After I had setup the set of servers, and configured ProxySQL to redirect the incoming connection from my user m8_test to my MySQL8 setup, I had turn on my Java test application ... and with my surprise I received an error:

Caused by:

1

      com.mysql.cj.core.exceptions.CJException: Unknown system variable 'query_cache_size'

Well ok MySQL8 doesn't have Query cache, but why I got this error?

I did point the application to MySQL8 directly and it worked fine.

Just to be sure this is something restricted to the Java connector, I did a test with a perl, and I was able to access and …

Our clients operate on a variety of platforms, and RDS (Amazon Relational Database Service) Aurora has received quite a bit of attention in recent times. On behalf of our clients, we look beyond the marketing, and see what the technical architecture actually delivers.  We will address specific topics in individual posts, this time checking out what the Aurora architecture means for write and caching behaviour (and thus performance).

What is RDS Aurora?

First of all, let’s declare the baseline.  MySQL Aurora is not a completely new RDBMS. It comprises a set of Amazon modifications on top of stock Oracle MySQL 5.6 and 5.7, implementing a different replication mechanism and some other changes/additions.  While we have some information (for instance from the “deep dive” by AWS VP Anurag Gupta), the source code of the Aurora modifications …

In this blog post, I will talk about archiving MySQL tables in ClickHouse for storage and analytics.

Why Archive?

Hard drives are cheap nowadays, but storing lots of data in MySQL is not practical and can cause all sorts of performance bottlenecks. To name just a few issues:

1. The larger the table and index, the slower the performance of all operations (both writes and reads)
2. Backup and restore for terabytes of data is more challenging, and if we need to have redundancy (replication slave, clustering, etc.) we will have to store all the data N times

The answer is archiving old data. Archiving does not necessarily mean that the data will be permanently removed. Instead, the archived data can be placed into long-term storage (i.e., AWS S3) or loaded into a …