Recently, I had to go through crash recovery of a large MariaDB 10.1.21 instance.  After starting MariaDB, I started tailing the error logs expecting to wait many minutes while InnoDB was scanning ibd files.  I was surprised (and actually delighted) with this:

[...] [...]:34:36 [...] [Note] InnoDB: Reading tablespace information from the .ibd files... [...]:34:53 [...] [Note] InnoDB: Processed

MySQL Enterprise Backup Team is pleased to announce major improvements in incremental backup performance starting with release 4.1.

Introduction

The current incremental backup algorithm scans all the tables to gather changed pages even if very few tables are modified since the previous backup and thus results in a 'full-scan' incremental backup. This may result in increment backups requiring the same amount of time as full backup because it scans all the tables. The new algorithm aims to eliminate this extra time.

The new algorithm scans only those tables that have been modified since the previous backup. This algorithm relies on modification time, which is similar to an earlier improvement made for full backup. That full backup algorithm is known as optimistic full backup, hence new improvement is named …

Running out of disk space is something which, of course, should never happen as we all setup monitoring and alerting and only run well behaved applications. But when it does happen we want things to fail gracefully.

So what happens when mysqld runs out of disk space?
The answer is: It depends

1. It might start to wait until disk space becomes available.
2. It might crash intentionally after a 'long semaphore wait'
3. It might return an error to the client (e.g. 'table full')
4. It might skip writing to the binlog (see binlog_error_action )

What actually happens might depend on the filesystem and OS.

Fixing the disk space issue can be done by adding more space or cleaning up some space. The later can often be …

MySQL Group Replication has been released since MySQL 5.7.17.
A quick start guide can be on the following URL
http://mysqlhighavailability.com/mysql-group-replication-a-quick-start-guide/

If there is a network partition between a group of Servers, it may introduce arbitration to find out and determine the next action for the Group of the Servers.
For documentation about Network Partitioning with Group Replication, please refer to the following URL::
https://dev.mysql.com/doc/refman/5.7/en/group-replication-network-partitioning.html

This blog is written to introduce my 'demo' version of arbitrator / watchdog.   From here onwards, I refer this arbitrator as gr_watchdog.
Another public arbitrator from Matt Lord can also be found on :
https://github.com/mattlord/myarbitratord
As an example, an application connecting to a group of servers with 5 MySQL instances …

The MariaDB subquery cache feature added in MariaDB 5.3 is not widely known. Let’s see what it is and how it works.

What is a subquery cache?

The MariaDB subquery cache optimizes the execution of correlated subqueries. Correlated subqueries refer to a value from the parent query. For example:

SELECT id FROM product WHERE price NOT IN (SELECT MAX(price) FROM product GROUP BY category);

MariaDB only uses this optimization if the parent query is a SELECT, not an UPDATE or a DELETE. The subquery results get cached only for the duration of the parent query.

MariaDB added the subquery cache in v5.3. It is controlled by …

This is a rant. It’s a strong one mainly because of what I’ve been dealing with over the past few days. But it’s still just a rant, so I’m going to exaggerate 😛. I’ve been with my employer for several years, and a lot of the stuff I’m writing about isn’t really new. I think most of it has been like this for years. I didn’t really pay attention to this stuff in the past because I didn’t have to. I didn’t want to either1, but now our team is handling ops and I have to care 😐.

Doing it wrong with MySQL

We use async, bidirectional replication. It’s a nightmare.

Using async replication means you don’t care about replicas, basically by definition. If the master isn’t waiting for replicas, then they can fall arbitrarily behind, crash, fail, whatever and the master will happily keep going. You can use hacks like delaying binlog commits on the master to improve parallelization on the …

Thank you everyone who attended our Webinar on “Monyog v7.04 demonstration & Roadmap Update”.

During the webinar, Shree gave a complete walkthrough of the all new Monyog v7.04. He also shared the product roadmap along with the performance improvements for bigger deployments.

Here’s the complete video for all those who couldn’t attend the webinar.

We hope you found the webinar useful. We will be conducting more webinars in upcoming weeks. To keep yourself updated, subscribe to our blogs.

Download a free trial of Monyog here.

The post Highlights: Monyog v7.04 demonstration & Roadmap Update appeared first on Webyog Blog.

This post is a lab experiment learning from migration to the Percona Xtradb Cluster (Galera) and a very unexpected DEADLOCK scenario which took me back to basics. (root@localhost) [test]>insert into…

The post MySQL to Galera Cluster Migration, Deadlock, Back to basics first appeared on Change Is Inevitable.

In this blog post, I’ll look for the bottleneck that prevented the performance in my previous post from achieving better results.

The powerful machine I used in the tests in my previous post has a comparatively slow disk, and therefore I expected my tests would hit a point when I couldn’t increase performance further due to the disk speed.

Hardware configuration:

Processors: physical = 4, cores = 72, virtual = 144, hyperthreading = yes
Memory: 3.0T
Disk speed: about 3K …

This maintenance release introduces a long requested feature – HEX-dumping of binary data – and adds a number of non-critical bug fixes.

Changes as compared to MySQL GUI 12.4 include:

Features:

* Added an option to HEX-dump binary data in Export as SQL and in Scheduled Backup.
* In read-only mode FLUSH-statements can now be executed from the GUI as well as editor, except for ‘FLUSH TABLE WITH READ LOCK’ (as we don’t allow acquiring explicit LOCKS in read-only mode).

Bug Fixes:

* On enabling HTTP, SSL or SSH checkbox in the connection manager, the checkbox wasn’t redrawn automatically. The checkbox were re-drawn only on hovering over them or switching to another tab in the connection window
* In Table Diagnostics, clicking on Analyse executed same query …