In this blog post, we talk about how existing client connections are handled by the Tungsten Connector when a manual master role switch is invoked and how to adjust that behavior.

When a graceful switch is invoked via cctrl or the Tungsten Dashboard, by default the Connector will wait for five (5) seconds to allow in-flight activities to complete before forcibly disconnecting all active connections from the application side, no matter what type of query was in use.

If connections still exist after the timeout interval, they are forcibly closed, and the application will get back an error.

This configuration setting ONLY applies to a manual switch. During a failover caused by loss of MySQL availability, there is no wait and all connections are force-closed immediately.

This timeout is adjusted via the tpm option …

In a previous post, we discussed how you can take control of the failover process in ClusterControl by utilizing whitelists and blacklists. In this post, we are going to discuss a similar concept. But this time we will focus on integrations with external scripts and applications through numerous hooks made available by ClusterControl.

Infrastructure environments can be built in different ways, as oftentimes there are many options to choose from for a given piece of the puzzle. How do we define which database node to write to? Do you use virtual IP? Do you use some sort of service discovery? Maybe you go with DNS entries and change the A records when needed? What about the proxy layer? Do you rely on ‘read_only’ value for your proxies to decide on the writer, or maybe you make the required changes directly in the configuration of …

Introduction

What is the X-DevApi? From insidemysql.com there is a definition of the X-DevAPI and its features in the following paragraphs:

The X DevAPI is the common client-side API used by all connectors to abstract the details of the X Protocol. It specifies the common set of CRUD-style functions/methods used by all the official connectors to work with both document store collections and relational tables, a common expression language to establish query properties such as criteria, projections, aliases, and a standard set of additional database management features for handling things like transactions, indexes, etc.

The fact that most of these features share the same format and API between connectors, makes the X DevAPI a perfect fit for modern polyglot development environments such as microservices, and the fact that they are based on a …

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: …

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 …

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 …

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): …

MySQL partitioning makes data distribution of individual tables (typically we recommend partition for large & complex I/O table for performance, scalability and manageability) across multiple files based on partition strategy / rules. In very simple terms, different portions of table are stored as separate tables in different location to distribute I/O optimally. The user defined division of data by some rule is known as partition function, In MySQL we partition data by RANGE of values / LIST of values / internal hashing function / linear hashing function. By restricting the query examination on the selected partitions by matching rows increases the query performance by multiple times compared to the same query on a non partitioned table, This methodology is also called partition pruning (trimming of unwanted partitions), Please find below example of partition pruning:

There was an interesting but hard to read post on StackOverflow about how 'insert select delete' data from a MySQL JSON data type column.  The first line of the writer's problem is a little confusing '
In order to record user mac_address and count mac_address to restrict user login's pc or notebook to control user available max for example (it's work)' but the examples reveled more about what was desired. The idea was to track MAC address used by various users and the author of the question was wondering how to up data a JSON Array of values with JSON_INSERT.  INSERT is for inserting and the better choice would be JSON_ARRAY_APPEND or JSON_ARRAY_INSERT.    But what caught my eye was the second question: Select sql command for json column ? could be …

Now that MySQL 8.0 GA is out for almost 3 months, let’s see the status of how it’s integrated with Drupal, a very popular CMS using MySQL.

For people having already a Drupal site and that wants to upgrade to MySQL 8.0, please check this post.

Now if you want to use MySQL 8.0 with a fresh new Drupal 8, let’s have a look how does that work.

Drupal 8.5

Drupal 8.5.5 is the latest available stable release from July 4th 2018.

There is no notes about supporting MySQL 8.0. So let’s try it.

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