Dear Reader,

Hi! I probably don’t know you, but I’d like to make this blog better for you. If you’re disabled—for example, perhaps you use a screen reader, a special device, or have other needs that I might not anticipate, I’d really love your feedback on what I can do to make my content easier for you to read and enjoy.

A couple of things I’ve been thinking about recently:

• If you use a screen reader, does the navigation or other stuff get in the way?
• If you use some device to do something like, I dunno, convert my RSS feed to podcasts and listen in the subway, how well does that work?
• What should I do if I want to include a complicated equation? Use an image, use something like MathJax, mark it as skippable for screen readers?
• If I include images, does it matter what I name them? How good of an experience is the image I included above?
• What can I do to …

This Log Buffer Edition covers some of the niftiest blog posts from Oracle, SQL Server and MySQL.

Oracle:

• OBIEE 11g and Essbase – Faking Federation Using the GoURL.
• You can use one of these to link an exception name with an Oracle error number. Once you have done this, you can use the exception name in the exception block which follows the declaration.
• This is a short post to help out any “googlers” looking for an answer to why their 12.1.0.5 EM Cloud …

Recently we released an updated version of our Percona Toolkit with an important update for pt-online-schema-change if you use MySQL 5.6. A new parameter has been added, analyze-before-swap. What does it do? Let me explain it in more detail.

A bug not a bug

A customer contacted us because pt-online-schema-change caused hundred of queries to get stuck after the ALTER was done. All those queries were trying read from the altered table but for some reason the queries never finished. Of course, it caused downtime. The reason behind this is this “bug not a bug”:

http://bugs.mysql.com/bug.php?id=78289

As a summary, if you are running 5.6 with persistent stats enabled (which it is by default), the optimizer in some …

And by MySQL Ecosystem here, I do not only include Oracle but also MariaDB.

So I am annoyed, not overly annoyed (probably also a little disappointed), but enough to do something about it (write this post).  In the last days, two blog posts - relayed in social medias - were published by MySQL vendors (I am not linking to the posts, it is a waste of time for the reader - see below - and they can

The binary log contains “events” that describe database changes. On a basic installation with default options, it's not turned on. This log is essential for accommodating the possible following requirements:

Replication: the binary log on a master replication server provides a record of the data changes to be sent to slave servers. Point in Time recovery: allow to recover a database from a full

db4free.net finally runs MySQL 5.7 which was released on October 21.

Rather than upgrading the existing MySQL server I set up a new MySQL 5.7 server. This is cleaner and it helps to get rid of accounts which are no longer used.

For active users, the MySQL 5.6 server will stay online

until January 15, 2016.

You can access it on port 3307 (the new MySQL 5.7 server will again run on MySQL’s default port 3306).

Users who want to keep their data need to migrate it to the new server:

• create a backup of your data on the MySQL 5.6 server
• signup for a new db4free.net account
• restore your backup in the new MySQL 5.7 server

If you use the MySQL default client and …

In the last couple of weeks, there have been a few blog posts about benchmarks comparing the performance of various versions of MySQL and variants such as MariaDB. There’s also been some analysis of the results using formal models such as Neil Gunther’s Universal Scalability Law.

What can the Universal Scalability Law (USL) teach us about the performance characteristics of these systems, as revealed by the benchmarks? To find out, I’ll examine one particular benchmark, MariaDB 10.1 and MySQL 5.7 performance on commodity hardware.

The context for this benchmark, in a nutshell, is that MySQL 5.7 was just released as GA, and the published performance results are spectacular, from the point of view of throughput on large servers. Although this is good, showing that MySQL can scale to do lots of work on large servers, the MariaDB …

In the last couple of weeks, there have been a few blog posts about benchmarks comparing the performance of various versions of MySQL and variants such as MariaDB. There’s also been some analysis of the results using formal models such as Neil Gunther’s Universal Scalability Law.

What can the Universal Scalability Law (USL) teach us about the performance characteristics of these systems, as revealed by the benchmarks? To find out, I’ll examine one particular benchmark, MariaDB 10.1 and MySQL 5.7 performance on commodity hardware.

Many of my recent engagements have been all around strategy to implement Real Time Big Data Analytics: Computing hardware cost of extending a single table collection with MariaDB and Parallel Query found in the Spider storage engine to offload columnar MPP storage like InfiniDB or Vertica.

As of today Parallel Query is only available from releases of MariaDB Spider supported by spiral arms. The more efficient way to use parallel query with Spider can be done on group by, and count queries that use a single spider table. In such case Spider Engine will execute query push down AKA map reduce.

Spider gets multiple levels of parallel execution for a single partitioned tables.

First level is per backend server:
The way to actually tell spider to scan different backends in concurrency is to set  spider_sts_bg_mode=1

Other level is per …

The new Mydumper 0.9.1 version, which includes many new features and bug fixes, is now available.  You can download the code from here.

A significant change included in this version now enables Mydumper to handle all schema objects!!  So there is no longer a dependency on using mysqldump to ensure complex schemas are backed up alongside the data.

Let’s review some of the new features:

Full schema support for Mydumper/Myloader

Mydumper now takes care of backing up the schema, including Views and Merged tables. As a result, we now have these new associated options:

-d, --no-data Do not dump table data
-G, --triggers Dump triggers
-E, --events Dump events
-R, …