You have created a large database with thousands of tables (> 5000 in MySQL 5.6). Then you want to create a backup using xtrabackup. Or, if it is a Galera cluster, you have to recover a galera node using wsrep_sst_method=xtrabackup[-v2].

Unfortunately it fails and the following is emitted in the Job Logs messages:

xtrabackup: Generating a list of tablespaces
2015-11-03 19:36:02 7fdef130a780  InnoDB: Operating system error number 24 in a file operation.
InnoDB: Error number 24 means 'Too many open files'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/operating-system-error-codes.html
InnoDB: Error: could not open single-table tablespace file ./DB75/t69.ibd

In this case you can simply increase the open_files_limit of the MySQL server(s) by going to Manage > Configurations, click on Change Parameter.

…

Requires ClusterControl 1.2.11 or later. Applies to MySQL single instances, replications and Galera clusters.

You have created a large database with thousands of tables (> 5000 in MySQL 5.6). Then you want to create a backup using xtrabackup. Or, if it is a Galera cluster, you have to recover a galera node using wsrep_sst_method=xtrabackup[-v2].

Unfortunately it fails and the following is emitted in the Job Logs messages:

xtrabackup: Generating a list of tablespaces
2015-11-03 19:36:02 7fdef130a780  InnoDB: Operating system error number 24 in a file operation.
InnoDB: Error number 24 means 'Too many open files'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/operating-system-error-codes.html
InnoDB: Error: could not open single-table tablespace file ./DB75/t69.ibd

In this case …

http://www.itnews.com/article/3004953/use-oracles-database-watch-out-for-this-dec-1-deadline.html

Companies that use a standard edition of Oracle’s database software should be aware that a rapidly approaching deadline could mean increased licensing costs.

Speaking from experience (at both MySQL AB and Open Query), typically, licensing/pricing changes such as these act as a motivator for migrations.

Migrations are a nuisance (doesn’t matter from/to what platform) and are best avoided as they’re intrinsically painful, costly and time-consuming. Smart companies know this.

When asked in generic terms, we generally recommend against migrations (even to MySQL/MariaDB) for the above-mentioned practical and business reasons. There are also technical reasons. I’ll list a …

The OPTIMIZE TABLE statement provides allows MySQL DBAs to reorganize physical table storage in order to achieve two main goals:

1. Improve IO efficiency for reads/writes against the table,
2. Reclaim unused storage space.

For InnoDB tables, OPTIMIZE is implemented via ALTER TABLE operation. This is true in all MySQL versions, however MySQL 5.7.4 introduced a change that may catch many users off guard and is therefore worth highlighting. Theory The InnoDB storage engine does not directly support OPTIMIZE. Instead, when a DBA invokes OPTIMIZE TABLE x, InnoDB executes ALTER TABE x FORCE. In MySQL versions prior to 5.7.4, OPTIMIZE is not an online operation i.e. the table is locked and DML operations against the table are not allowed until OPTIMIZE finishes.
MySQL 5.7.4 introduces a significant change around OPTIMIZE, namely the ALTER TABLE operation now uses  …

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 …