When I first blogged about a potential workaround for MySQL error 1070, I received a suggestion in the comments that my workaround might be a useful trick with MariaDB virtual columns or MySQL 5.7 generated columns. Although I've already blogged about a simplified version of my original workaround, the arrival of the MySQL 5.7.7 release candidate inspired me to try an even simpler implementation using generated columns.
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[Read more]Recently in my slave server there was a full disk error because of the huge size of binary logs.Which is lead to critical error and BUG report which is still stays as open:
http://bugs.mysql.com/bug.php?id=72437
So the issue was a partition problem which in partitioning stage
haven’t been specified for “/” (root) filesystem. But in “/home”
there were left enough space.
The quick decision was to change binary and relay log
location(path) to “/home”.
But there was a great challenge to get real working slave again.
Now we will explore all steps in our test virtual machine.
Test conditions for me:
1. CentOS 6.5 (x86_64) (both master and slave)
2. MySQL 5.6.19 GA (from official yum repo) (both master and
slave)
Master my.cnf:
# BINARY LOGGING # server_id = …[Read more]
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
…
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. 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 …
[Read more]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.
…
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Complimenting the expanded CREATE USER syntax introduced in
MySQL Server 5.7.6 is more useful ALTER USER
syntax. Before MySQL Server 5.7.6, ALTER USER
could only be used to expire a user’s password. That’s pretty
limited. With changes made in MySQL Server 5.7.6, a better
distinction is made between privilege-level attributes (those
which are managed via GRANT and REVOKE
statements) and account-level attributes (those managed using
CREATE USER and ALTER USER
statements). MySQL has a long history of confusing these –
for example, requiring a GRANT …
I use a Fedora 20 VM image to teach Oracle and MySQL technology. Last week, I expanded the Fedora VM image to support a full LAMP stack. This blog shows you how to install Ruby on Fedora and successfully generate the Rails gems.
Connect as the root user and use yum to install the
libraries. My approach is by library or small groups. Naturally,
you start with the ruby library.
yum install ruby |
You will see the following:
Loaded plugins: langpacks, refresh-packagekit mysql-connectors-community | 2.5 kB 00:00 mysql-tools-community | 2.5 kB 00:00 mysql56-community | 2.5 kB 00:00 pgdg93 | 3.6 kB 00:00 updates/20/x86_64/metalink … |
Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels.
Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave with INSERT/UPDATE and with READ-COMMITED and REPEATABLE-READ Isolation levels. I’m creating a small table data_col with few records. Initially, this test case was written by Bill Karwin to explain details to customer, but here I have used a bit modified test case.
CREATE TABLE data_col (dataname VARCHAR(10), period INT, expires DATE, host VARCHAR(10));
INSERT INTO data_col VALUES (‘med1′, …
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