Recently, I’ve been looking into issues with the interactions between MySQL asynchronous replication and Galera replication. In this blog post, I’d like to share what I’ve learned.

MySQL asynchronous replication and Galera replication interactions are complicated due to the number of factors involved (Galera replication vs. asynchronous replication, replication filters, and row-based vs. statement-based replication). So as a start, I’ll look at an issue that came up with setting up an asynchronous replication channel between two Percona XtraDB Cluster (PXC) clusters.

Here’s a view of the desired topology:

The Problem

We want to set up an asynchronous replication channel between two PXC …

From time to time I see pattern matching queries with conditions that look like this: “where fieldname like ‘%something%’ “. MySQL cannot use indexes for these kinds of queries, which means it has to do a table scan every single time.

(That’s really only half true — there are the FullText indexes. In another blog post I will cover FullText indexes as well.)

I recently was trying to find a solution, and my friend Charles Nagy reminded me of Trigrams. Let me show you the Trigram of the name Daniel:

daniel:
dan
ani
nie
iel

But how is this useful?

Let me show you an example. You have the following email …

We’re excited to announce a major update to our tutorial “Database Load Balancing for MySQL and MariaDB with ProxySQL”

ProxySQL is a lightweight yet complex protocol-aware proxy that sits between the MySQL clients and servers. It is a gate, which basically separates clients from databases, and is therefore an entry point used to access all the database servers.

In this new update we’ve…

• Updated the information about how to best deploy ProxySQL via ClusterControl
• Revamped the section “Getting Started with ProxySQL”
• Added a new section on Data Masking
• Added new frequently asked questions (FAQs)

Load balancing and high availability go …

MySQL is again a part of the FOSSASIA - Free Open Source Summit Asia  2018 which will be hold on March 22-25, 2018 in Singapore. Do not miss to come to our booth in exhibition area as well as do not miss MySQL related talks in Database track... See some of them below and at Fossasia schedule:

Saturday, March 24, 2018:

• 10:00-11:00 MySQL Community Gathering - come to join to the MySQL meetup or other community! Come to Lounge area of the Summit to meet Ricky Setyawan.
• 11:30-11:55 Database Lightning Talk by Ricky Setyawan, the Principal Sales Consultant
• 17:00-17:25 Breaking through with MySQL 8.0, by Ricky Setyawan, the Principal Sales Consultant

Sunday, March 25, 2018:

…

NDB is mainly an In-memory database. We have however also the possibility to
store non-indexed columns on disk. This data uses a page cache as any
other normal disk-based DBMS.

Interestingly with the increases of memory sizes one could think that
disk data becomes less important for MySQL Cluster. The answer is actually
the opposite.

The reason is again the HW development. NDB is designed with predictable
latency as a very basic requirement. In the past disks meant hard drives. Access
time to a hard disk was several milliseconds at best. Given that our requirement
was to handle complex transactions within 10 milliseconds disk data storage
was out of the question.

Modern HW is completely different, they use SSD devices, first attached through
the SATA interface that enabled up to around 500 MByte per second and
a few thousand IO …

I just read an article called Low-Overhead Asynchronous Checkpointing in
Main-Memory Database Systems. It was mentioned in a course in Database
Systems at Carnegie-Mellon University, see here.

In MySQL Cluster 7.6.4 we released a new variant of our checkpointing designed
for modern HW with TBytes of main memory. I think studying this implementation
will be very worthwhile both for users of NDB, but also for researchers in DBMS
implementations. It implements a new class of checkpoint algorithms that is currently
a research topic in the database research community.

It was interesting to compare our approach that I called Partial LCP with approaches
taken by other commercial in-memory databases and with the approach presented
in the paper.

LCP is Local …

Percona announces the release of Percona Toolkit 3.0.8 on March 16, 2018.

Percona Toolkit is a collection of advanced open source command-line tools, developed and used by the Percona technical staff, that are engineered to perform a variety of MySQL®, MongoDB® and system tasks that are too difficult or complex to perform manually. With over 1,000,000 downloads, Percona Toolkit supports Percona Server for MySQL, MySQL, MariaDB®, Percona Server for MongoDB and MongoDB.

Percona Toolkit, like all Percona software, is free and open source. You can download packages from the website or install from official repositories.

This …

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

SCALE16x is over. Percona had a large showing — both Peter Zaitsev & myself had talks, and the booth in the expo hall saw Rick Golba, Marc Sherwood, and Dave Avery also pop by. The lead scanner suggests we had several hundred conversations — read Dave Avery’s summary. My talk went well, though during Q&A the number of questions I got about MariaDB Server was quite interesting (considering it wasn’t part of my talk!). It is clear people are concerned about compatibility (because I spent close to 45 minutes after my talk answering Q&A outside too).

I got to catch up with …

FromDual has the pleasure to announce the release of the new version 2.0.0 of its popular MySQL, Galera Cluster and MariaDB multi-instance environment MyEnv.

The new MyEnv can be downloaded here.

In the inconceivable case that you find a bug in the MyEnv please report it to the FromDual bug tracker.

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 1.1.x to 2.0.0

# cd ${HOME}/product
# tar xf /download/myenv-2.0.0.tar.gz
# rm -f myenv
# ln -s myenv-2.0.0 myenv

Plug-ins

If you are using plug-ins for …

FromDual has the pleasure to announce the release of the new version 2.0.0 of its popular MySQL, Galera Cluster and MariaDB multi-instance environment MyEnv.

The new MyEnv can be downloaded here. How to install MyEnv is described in the MyEnv Installation Guide.

In the inconceivable case that you find a bug in the MyEnv please report it to the FromDual bug tracker.

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 1.1.x to 2.0.0

MyEnv 2.0.0 requires an new PHP …