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Mastering Continuent Clustering Series: Global Clustering with Active/Active Meshed Replication

Did you know that Continuent Clustering supports having clusters at multiple sites world-wide with active-active replication meshing them together?

Not only that, but we support a flexible hybrid model that allows for a blended architecture using any combination of node types. So mix-and-match your highly available database layer on bare metal, Amazon Web Services (AWS), Azure, Google Cloud, VMware, etc.

The possibilities are endless, as is the business value. This strong topology allows you to have all the benefits of high availability with local reads and writes, while spreading that data globally to be accessible in all regions. Latency is limited only by the WAN link and the speed of the target node.

This aligns perfectly with the distributed Software-as-a-Service (SaaS) model where customers and data span the globe. Applications have access to ALL the …

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InnoDB Cluster in a Nutshell: Part 2 MySQL Router

MySQL InnoDB Cluster is an Oracle High Availability solution that can be easily installed over MySQL to provide high availability with multi-master capabilities and automatic failover. In the previous post we presented the first component of InnoDB Cluster, group replication. Now we will go through the second component, MySQL Router.  We will address MySQL Shell in a final instalment of this three-part series. By then, you should have a good overview of the features offeed by MySQL InnoDB Cluster.

MySQL Router

This component is responsible for distributing the traffic between members of the cluster. It is a proxy-like solution to hide cluster topology from applications, so applications don’t …

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How to Control Replication Failover for MySQL and MariaDB

Automated failover is pretty much a must have for many applications - uptime is taken for granted. It’s quite hard to accept that an application is down for 20 or 30 minutes because someone has to be paged to log in and investigate the situation before taking action.

In the real world, replication setups tend to grow over time to become complex, sometimes messy. And there are constraints. For instance, not every node in a setup makes a good master candidate. Maybe the hardware differs and some of the replicas have less powerful hardware as they are dedicated to handle some specific types of the workload? Maybe you are in the middle of migration to a new MySQL version and some of the slaves have already been upgraded? You’d rather not have a master in more recent version replicating to old replicas, as this can break replication. If you have two datacenters, one active and one for disaster recovery, you may prefer to pick master …

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Descending index in MySQL 8.0

MySQL 8.0 has come with a list of new features for DBA’s ,we will discuss the new feature in MySQL 8.0 which supports Descending index.Prior to MySQL 8.0 (i.e MySQL 5.6 and 5.7) creating desc index syntax was supported but desc keyword was ignored, Now in MySQL 8.0 release descending index is extended are supported.

What is index?

  • Indexes play an important role in performance optimization  and they are used frequently to speed up access to particular data and reduce disk I/O operations .
  • To understand index easily you can imagine a book,every book has an index with content referring to a page number.If you want to search something in a book you first refer to the index and get the page number and then get the information in the page,like this the indexes in MySQL will tell you the row with matching data.

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This Week in Data with Colin Charles 45: OSCON and Percona Live Europe 2018 Call for Papers

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Hello again after the hiatus last week. I’m en route to Portland for OSCON, and am very excited as it is the conference’s 20th anniversary! I hope to see some of you at my talk on July 19.

On July 18, join me for a webinar: MariaDB 10.3 vs. MySQL 8.0 at 9:00 AM PDT (UTC-7) / 12:00 PM EDT (UTC-4). I’m also feverishly working on an update to MySQL vs. MariaDB: Reality Check, now that both MySQL 8.0 and MariaDB Server 10.3 are generally available.

Rather important: …

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Mastering Continuent Clustering Series: Tuning for High-Latency Links

What if I want the cluster to be less sensitive to network, especially WAN latency?

Continuent Clustering supports having clusters at multiple sites with active-active replication meshing them together.

This is extraordinarily powerful, yet at times high network latency can make it harder for messaging between the sites to arrive in a timely manner.

This is evidenced by seeing the following in the Manager log files named tmsvc.log:

2018/07/08 16:51:05 | db3 |  INFO [Rule_0604$u58$_DETECT_UNREACHABLE_REMOTE_SERVICE1555959201] - CONSEQUENCE: [Sun Jul 08 16:51:04 UTC 2018] CLUSTER global/omega(state=UNREACHABLE)
...
2018/07/08 16:51:42 | db3 |  INFO [Rule_2025$u58$_REPORT_COMPONENT_STATE_TRANSITIONS1542395297] - CLUSTER 'omega@global' STATE TRANSITION UNREACHABLE => ONLINE

The delta is 37 seconds in the above example between state=UNREACHABLE and UNREACHABLE => ONLINE

The default …

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On MySQL and Intel Optane performance

Recently, Dimitri published the results of measuring MySQL 8.0 on Intel Optane storage device. In this blog post, I wanted to look at this in more detail and explore the performance of MySQL 8, MySQL 5.7 and Percona Server for MySQL using a similar set up. The Intel Optane is a very capable device, so I was puzzled that Dimitri chose MySQL options that are either not safe or not recommended for production workloads.

Since we have an Intel Optane in our labs, I wanted to run a similar benchmark, but using settings that we would recommend our customers to use, namely:

  • use innodb_checksum
  • use innodb_doublewrite
  • use binary logs with sync_binlog=1
  • enable (by default) Performance …
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How to perform Schema Changes in MySQL & MariaDB in a Safe Way

Before you attempt to perform any schema changes on your production databases, you should make sure that you have a rock solid rollback plan; and that your change procedure has been successfully tested and validated in a separate environment. At the same time, it’s your responsibility to make sure that the change causes none or the least possible impact acceptable to the business. It’s definitely not an easy task.

In this article, we will take a look at how to perform database changes on MySQL and MariaDB in a controlled way. We will talk about some good habits in your day-to-day DBA work. We’ll focus on pre-requirements and tasks during the actual operations and problems that you may face when you deal with database schema changes. We will also talk about open source tools that may help you in the process.

Test and rollback scenarios

Backup

There are many ways to lose your data. Schema upgrade failure is …

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Porting this Oracle MySQL feature to MariaDB would be great ;-)

Oracle has done a great technical work with MySQL. Specifically a nice job has been done around security. There is one useful feature that exists in Oracle MySQL and that currently does not exist in MariaDB. Oracle MySQL offers the possibility from within the server to generate asymetric key pairs. It is then possible use ...continue reading "Porting this Oracle MySQL feature to MariaDB would be great ;-)"

Why MySQL Stored Procedures, Functions and Triggers Are Bad For Performance

MySQL stored procedures, functions and triggers are tempting constructs for application developers. However, as I discovered, there can be an impact on database performance when using MySQL stored routines. Not being entirely sure of what I was seeing during a customer visit, I set out to create some simple tests to measure the impact of triggers on database performance. The outcome might surprise you.

Why stored routines are not optimal performance wise: short version

Recently, I worked with a customer to profile the performance of triggers and stored routines. What I’ve learned about stored routines: “dead” code (the code in a branch which will never run) can still significantly slow down the response time of a function/procedure/trigger. We will need to be careful to clean up what we do not need.

Profiling MySQL stored functions

Let’s compare these four simple stored functions (in MySQL 5.7): …

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