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Showing the hidden tables in MySQL 8 data dictionary

The freshly released MySQL 8.0 includes a data dictionary, which makes MySQL much more reliable. Thanks to this features, we don't have any '.frm' files, and querying the information_schema is 30x to 100x faster than previous versions.

One drawback of the implementation is that the data dictionary tables are hidden by design.

While the reason is fully understandable (they don't want to commit on an interface that may change in the future) many curious users are disappointed, because openness is the basis of good understanding and feedback.

The problem to access the dictionary tables can be split in three parts:

  • Finding the list of tables; …
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MySQL at Oracle Open World 2016

MySQL is a growing presence at Oracle Open World. While most of the headlines belong to the main products, where Oracle services are aiming at world domination, MySQL shared the spotlight, as it was announced to be part of Oracle database cloud. It seems a logical move for Oracle: after all the effort to make MySQL 5.7 the biggest release ever, it stands to reason that it is offered as a competitive feature in its own database as a service.

With this offer, Oracle is applying enterprise pricing and methodologies to a target of emerging companies. MySQL in the Oracle cloud differs from the competition by a few key points:

  • It's only MySQL 5.7. While this is the most advanced MySQL server …
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Introducing BakaSQL, the MySQL web-based sandbox for query execution

BakaSQL: a bit of history When I joined this new company I was already aware there was a lot of work to do. There was no DBA Team to speak of; any MySQL related task was handled by the sysadmins, and the company was growing as fast as you can imagine, with 15-20 new employees arriving each month, most of them in the IT department. For sure, there was much fun ahead.

During my first week in the new job  I immediately felt that something was not right. I was receiving too much DMLs to execute each day, spanning a wide set of servers, schemas an tables. This is not something I had seen before, so I started asking around what the reason behind it was.  It turned out that there were multiple reasons behind it:

  • there were known bugs in the applications that were never fixed
  • application configuration items were stored in MySQL, but there was no admin panel to modify them
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Moving binary logs to a different filesystem without downtime

Another day at the office...

"Whoa, the write workload on our statistical cluster has  suddendly increased by 20% and the filesystem that holds the binary logs is no longer large enough".

Of course, I had warned the boss about this possibility when I received those servers with that tiny 250G filesystem for binlogs, but my red flag was just ignored as usual.

So here we are, presto I get this new shiny 600G LUN, but we need to stop the damn MySQL server in order to repoint the log_bin variable to the new storage area.

Dunno about you, but the idea of waking up at 2am to just perform a variable change is not something that makes me particularly happy. Not to mention the maintenance period that is needed around it....

So, I decided to investigate a bit about the possibilities to do such change without stopping the service.

As we all know, the log_bin …

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Introducing the MySQL Cloud Service

The MySQL keynote at Oracle Open World 2016 announced the immediate availability of the MySQL Cloud Service, part of the larger Oracle Cloud offering. You can evaluate this now with a trial copy at cloud.oracle.com/mysql. MySQL server product manager Morgan Tocker gave two presentations at the event including a deep dive session.

This is the first release of the MySQL cloud service. As with all first releases there are some highlights and some pipeline features. All major cloud providers have MySQL offerings. AWS RDS (traditional, MAZ and Aurora) GCP Cloud SQL and Azure …

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First look at MySQL 8.0.0 Milestone

So, about ten days ago the MySQL Server Team released MySQL 8.0.0 Milestone to the world. One of the most unfortunate things about MySQL development is that it’s done behind closed doors, with the only hints of what’s to come arriving in maybe a note on a bug or such milestone releases that contain a lot of code changes. How much code change? Well, according to the text up on github for the 8.0 branch “This branch is 5714 commits ahead, 4 commits behind 5.7. ”

Way back in 2013, I looked at MySQL Code Size over releases, which I can again revisit and include both MySQL 5.7 and 8.0.0.

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Percona XtraDB Cluster 5.5.41-25.11.1 is now available

Percona announces the new release of Percona XtraDB Cluster 5.5.41-25.11.1 (rev. 855) on September 22, 2016. Binaries are available from the downloads area or our software repositories.

Bugs Fixed:

  • Due to security reasons ld_preload libraries can now only be loaded from the system directories (/usr/lib64, /usr/lib) and the MySQL installation base directory. This fix also addresses issue with where limiting didn’t work correctly for relative paths. Bug fixed #1624247.
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HAProxy – Mysql cluster on Docker

In this tutorial I am going to setup a HAProxy based cluster (layer 4) in Docker which would load balance to a set of Mysql nodes (again running on Docker).

Before I jump into how to get this done, I would like to explain a little more about few important terms : –

  • Docker – well, everybody knows this. Excellent implementation of Microservices architecture. nearly everybody is going for it, whether Redhat, Oracle, Microsoft, Apple. it has potential to containerize on any platform.
  • HAProxy – stands for High Availability Proxy, is an open source software TCP/HTTP Load Balancer and Reverse proxy solution which can run on Linux, Solaris, and FreeBSD. Most common use case for this product is to improve the performance and availability of servers by distributing the workload across multiple servers (e.g. web, application, database (yes, even Database)). So why do we need HAProxy? …
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MySQL 8.0 Labs: [Recursive] Common Table Expressions in MySQL (CTEs)

I realize that these last months I have not published anything... it's because I was quite busy developing a prominent feature: [Recursive] Common Table Expressions, also known as

  • [recursive] CTE,
  • [recursive] subquery factoring,
  • WITH [RECURSIVE] clause.

This feature is available today, in a Labs release of the MySQL Server.
In my post here, you will find more information: syntax, capacities, examples...
Feels good to have this big piece of work finally out!

InnoDB and Linux mount point.

In this blog we are going to share my recent experience with an issue which we faced during migration between two Ubuntu servers.

The activity was pretty simple, the client had bought a new machine with enhanced memory and faster disk, so the data has to be transferred to the new server and live MySQL replication has to be configured between the old and the new server.

For the hot and live data transfer we used xtrabackup’s stream method, the data transfer happened smoothly without any issue.

Everything was set and we had applied the log and followed the normal procedure to change the ownership of datadir to “mysql” and all the entries in the my.cnf were double checked.

When we intended to start mysql, the service didn’t come up instead we had a weird error as below.

MySQL Error:
——————

2016-08-31 22:35:27 9938 [ERROR] InnoDB: ./ibdata1 can't be opened in …
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