Taxonomy upgrade extras: logginggaleraclusterconflictdeadlockerror logerror

We typically suggest our customers to use our MySQL/Galera Cluster my.cnf configuration template to avoid MySQL configuration and performance problems.

And we are paranoid as well. Thus we enable all useful logging:

wsrep_log_conflicts = 1

…

Taxonomy upgrade extras: galeravmwaresnapshot

From time to time we see at Galera Cluster customer engagements the following, for me scary, warning in the MySQL error log:

[Warning] WSREP: last inactive check more than PT1.5S ago (PT7.06159S), skipping check

We mostly see this in VMware set-ups. Some further enquiry with the Galera developers did not give a satisfying answer:

This can be seen on bare metal as well - with poorly configured mysqld, O/S, or simply being overloaded. All it means is that this thread could not get CPU time for 7.1 seconds. You can imagine that access to resources in virtual machines is even harder (especially I/O) than on bare metal, so you will see this in …

After you install Ruby and build the Rails framework, you need to create the mysql gem. This blog post shows you how to create the mysql gem and how to write a simple Ruby program that queries the MySQL database.

The first step creates the mysql gem for Ruby programming:

yum install mysql

It should show you the following:

Fetching: mysql-2.9.1.gem (100%)
Building native extensions.  This could take a while...
Successfully installed mysql-2.9.1
Parsing documentation for mysql-2.9.1
Installing ri documentation for mysql-2.9.1
Done installing documentation for mysql after 0 seconds
1 gem installed

After you install the mysql Ruby Gem, you can write and …

The MySQL 5.7.7 JSON Lab release introduces a native JSON datatype. In part 1 of this blog post series, Rick Hillegas introduced the new functions for creating and manipulating JSON documents using the new native JSON data type. In this blog post we will be using some of the same sample tables and JSON documents as in part 1, so it will be helpful to read that blog post now, if you haven’t already.

Here we look closer at the functions provided to search through and peer into JSON documents to find values inside of them, and we’ll also cover a few utility functions as we go along. The functions described here are also summarized at the end of this blog for ease of reference.

Please note that the exact set of functions and their semantics may evolve …

The MySQL 5.7.7 JSON Lab release introduces a native JSON datatype. See Knut Anders Hatlen’s blog post for more details on this new datatype. In this release we also introduced a number of functions for creating and querying JSON documents. In this post we’ll explore the following new functions related to manipulating JSON documents:

• jsn_array()
• jsn_object()
• jsn_insert()
• jsn_remove()
• jsn_set()
• jsn_replace()
• jsn_append()
• jsn_merge()
• jsn_extract()

Dag Wanvik’s follow up blog …

In the MySQL 5.7.7 JSON labs release, we have introduced a new data type for storing JSON data in MySQL tables. Now you can do this:

mysql> CREATE TABLE employees (data JSON);
Query OK, 0 rows affected (0,01 sec)

mysql> INSERT INTO employees VALUES ('{"id": 1, "name": "Jane"}');
Query OK, 1 row affected (0,00 sec)

mysql> INSERT INTO employees VALUES ('{"id": 2, "name": "Joe"}');
Query OK, 1 row affected (0,00 sec)

mysql> select * from employees;
+---------------------------+
| data                      |
+---------------------------+
| {"id": 1, "name": "Jane"} |
| {"id": 2, "name": "Joe"}  |
+---------------------------+
2 rows in set (0,00 sec)

Sure, you could always store JSON data in a TEXT or VARCHAR column, but having a native data type for JSON provides some major benefits over that approach:

1. Document Validation

   Only …

New in MySQL 5.7.7, the MySQL sys schema (originally the ps_helper project) is now included by default within the MySQL server!

For those unfamiliar with the sys schema project, it is a database schema with a set of objects (views, stored procedures, stored functions, and table with a couple of triggers on it) that were implemented to give easy, human readable, DBA and Developer based use case access to the wealth of instrumentation data implemented primarily within Performance Schema, but also with various …

A good portion of the startups I meet and advise want to use the newest, hottest technology to build something that’s cool, but not technologically groundbreaking. I have yet to meet a startup building a time machine, teleporter or quantum social network that would actually require some amazing new tech. They have awesome new ideas with down-to-earth technical requirements, so I kept wondering why they choose this shiny (and risky) new stuff when all they need is a good ol’ trustworthy database. I think it’s because many assume that building the latest and greatest needs the latest and greatest!

It turns out that’s only one of three bad reasons (traps) why people go for the shiny and new. Reason two is people mistakenly assume older stuff is slow, not feature rich or won’t scale. “MySQL is sluggish,” they say. “Java is slow,” I’ve heard. “Python won’t scale,” they claim. None of it’s true.

…

First of all a disclaimer: I don’t work for Oracle nor do I speak for them. I believe this information to be correct, but for licensing questions, Oracle themselves have the final word.

With that out of the way, followers of this blog may have seen some of the results from my testing of actual CPU capacity with public clouds like Amazon Web Services, Microsoft Azure, and Google Compute Engine. In each of these cases, a CPU “core” was actually measured to be equivalent to an x86 HyperThread, or half a physical core. So when provisioning public cloud resources, it’s important to include twice as many CPU cores as the equivalent …

MySQL Fabric is a great tool for managing a farm of MySQL servers. In the last two posts you can see how High Availability Fail over and Sharding work. When things are working right, the group lookup_servers will look something like this:
server_uuid address status mode weight
------------------------------------ ----------- --------- ---------- ------
09d13be1-cdd0-11e4-8643-0800273b9c80 10.10.13.10 SECONDARY READ_ONLY 1.0
0f611996-cdd0-11e4-8643-0800273b9c80 10.10.13.20 SECONDARY READ_ONLY 1.0
11aae7e7-cdd0-11e4-8643-0800273b9c80 10.10.13.30 PRIMARY READ_WRITE 1.0

This is a three node farm with a PRIMARY for READ-WRITE operations and two …