I recently stumbled upon a very interesting post by Lukas Eder, where he describes 10 query transformations which do not depend on the database’s cost model. He posted it a couple of years ago, though when I read it, I assumed some portions of it may still be relevant today.

In the original post, several databases were tested to see if their internal optimizer will be able to automatically re-write the SQL queries and optimize them. In those tests, MySQL under-performed in several of the use cases (the tested version was MySQL 8.0.2, which was released on 2017-07-17).

Seeing those results, and given the previous evaluation was done almost two years ago, I thought that now can be a good chance to re-evaluate a few of those tests with the latest MySQL 8.0.16 (released on 2019-04-25), and demonstrate …

Overview The Skinny

In this blog post we will discuss how the managed cross-site replication streams work in a Composite Multi-Master Tungsten Cluster for MySQL, MariaDB and Percona Server.

Agenda What’s Here?

• Briefly explore how managed cross-site replication works in a Tungsten Composite Multi-Master Cluster
• Describe the reasons why the default design was chosen
• Explain the pros and cons of changing the configuration
• Examine how to change the configuration of the managed cross-site replicators

Cross-Site Replication A Very Brief Summary

In a standard Composite Multi-Master (CMM) deployment, the managed cross-site replicators pull Transaction History Logs (THL) from every remote cluster’s current master node. …

Feeling the FOMO? Now you don’t have to! With the Percona Live Open Source Database Conference 2019 Live Stream, you’ll practically be there in person, living the experience to the fullest. Our keynote stage features morning and lunchtime keynotes on Wednesday, May 29th and morning keynotes on Thursday, May 30th. Join us at home or on the go, from any corner of the world!

Percona is streaming the keynotes on Wednesday, May 29, 2019, at 9 AM CDT, Wednesday, May 29, 2019, at 1:25 PM CDT, and Thursday, May 30, 2019, at 9 AM, beginning at 9 AM CDT.

Keynote speakers include Continuent, VividCortex, AWS, Facebook, MariaDB Foundation, and many more. The keynote panel will feature topics such as the changing face of Open Source.

The list of keynote talks and speakers for each day is as follows:

…

In reply to Alex.

the backup user was created only on ic2 for pure demo sake. You’re right, it would be simpler to just allow that user to exist cluster-wide.
Regarding using Router to run the backup against, it would be ideal, but MEB does a local connection to the instance, so I’m afraid this is a limitation MEB has.
Thx
K.

LikeLike

In this blog, we will see how to do a flashback recovery or rolling back the data in MariaDB, MySQL and Percona.

As we know the saying  “All humans make mistakes”, following that in Database environment the data modified accidentally can bring havoc to any organisations.

Recover the lost data

• The data can be recovered from the latest full backup or incremental backup when data size is huge it could take hours to restore it.
• From backup of Binlogs.
• Data can also be recovered from delayed slaves, this case would be helpful when the mistake is found immediately, within the period of delay.

We can use anyone of the above ways or other that can help to recover the lost data, but what really matters is, What is the …

The Question Recently, a customer asked us:

Why would Tungsten Replicator be slow to apply to MySQL?

The Answer Performance Tuning 101

When you run trepctl status and see:
appliedLatency : 7332.394
like this on a slave, it is almost always due to the inability for the target database to keep up with the applier.

This means that we often need to look first to the database layer for the solution.

Here are some of the things to think about when dealing with this issue:

Architecture and Environment
√ Are you on bare metal?
√ Using the cloud?
√ Dev or Prod?
√ Network speed and latency?
√ Distance the data needs to travel?
√ Network round trip times? Is the …

errno: 24 - Too many open files
You might see this error inside MySQL's error log file or during mysql_upgrade operation.

Can't open file: ‘./db/table.frm' (errno: 24 - Too many open files)
To solve this issue, you will need to change the open files limit at system and db service level.

--> To check and change this limit at the system level, we use ulimit client tool to set it dynamically.

* Check current system open file limit.
root@test:~# ulimit -a core file size          (blocks, -c) 0 data seg …

(In the previous post, Part 4, we covered Compression and Bloom Filters)

In this blog post, we continue on our series of exploring MyRocks mechanics by looking at the configurable server variables and column family options. In our last post, I explained at a high level how compression and bloom filtering are applied to data files as they are initially flushed from immutable memtables and are subsequently passed through the compaction process. With that being covered, we should now have a clear understanding as to how data writing works in MyRocks and can start reviewing how data read requests are handled.

The Read Process

Let’s start off by talking about how read processes are handled at the file level. When a read request comes in, the first thing it needs to do is pull the …

At MariaDB Foundation, we are proud of MariaDB Server getting plenty of contributions. But we don’t want to get cocky, so here is an update about where we stand, and what we want to make happen. First, we have shown our contribution pride in several places. On 15 February 2019, I tweeted On code contributions, […]

The post On Contributions, Pride and Cockiness appeared first on MariaDB.org.

As continue of our previous announcement from March 14, please find below a list of shows & conferences where you can find MySQL team at:

• June 2019:

  • OpenSource Conference, Hokkaido, Japan, May 31-June 1, 2019

    • As we already announced MySQL is a Gold sponsor of this OS show. Our MySQL local team is going to staff the MySQL booth in the expo area as well having a MySQL talks as follows:
      • "MySQL Update + MySQL InnoDB Cluster" given by Daisuke Inagaki, the MySQL Principal Solutions Engineer. His talk is being hold on May 31 @13:55.
      …