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10 Newer Entries Showing entries 31 to 40 of 33583 10 Older Entries
MySQL Error Codes Out Of Context
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In the wrong context, almost anything can be funny, and MySQL’s error codes are no exception. A few weeks ago, things got a little loopy at VividCortex headquarters as we discovered some definitions that could be taken more than one way.

How It Began

It started with ER_M_BIGGER_THAN_D, which doesn’t sound like an error at all. Anyone who knows alphabetical order knows that M is bigger than D! Of course, the error is really about an attempt to define a decimal or float column wrongly.

Next was …

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MySQL 5.7: only_full_group_by Improved, Recognizing Functional Dependencies, Enabled by Default!
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I just posted on the Server team's blog, an account on my recent only_full_group_by work. We have made significant improvements in 5.7.5, worth a look!

MaxScale, manual control, external monitors and notification methods
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Wed, 2014-12-10 13:30mriddoch

One of the nice things about the "plug and play" approach of MaxScale is that people constantly find ways of using it that were not originally envisaged when we designed MaxScale. One such configuration that I have heard of from multiple sources is using monitoring outside of MaxScale itself. This post will discuss a little about how monitoring works and how it can be moved outside of MaxScale. In particular a simplified example will be presented which shows how to use the notification mechanism in Galera to control MaxScale's use of the nodes in a Galera cluster.

Monitoring Within MaxScale …

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MySQL 5.7: only_full_group_by Improved, Recognizing Functional Dependencies, Enabled by Default!
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Here’s an account of recent work which has kept me busy and excited for a few months. For those unfamiliar with the only_full_group_by sql mode, let me provide some context. I’ll use the world database, which can be downloaded from this MySQL Documentation page. You can find details on how to install the database on the same page. We have a table of countries and a table of languages spoken in each country. It’s a 1-to-N relationship: …

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Taskset: a useful tool to set CPU affinity
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Today at the #ukoug_tech14 I had the chance to attend to the Christo Kutrovky's session @kutrovsky (Pythian) about "Measuring Performance in Oracle Solaris & Oracle Linux". This session aimed to present how to measure system utilization in the Linux and Oracle Solaris operating systems and how to use these information for tuning and capacity planning. During this session we had a very good introduction to a bunch of performance monitoring tools that can be categorized in four categories (non …

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Recover MySQL root password without restarting MySQL (no downtime!)
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Disclaimer: Do this at your own risk! It doesn’t apply if you’re using Pluggable authentication and certainly won’t be usable if/when MySQL system tables are stored on InnoDB

Recover your root password with care!

What is the situation?

The situation is the classic “need to recover MySQL root password” but you cannot restart MySQL (because it is the master production server, or any other reason), which makes the –skip-grant-tables solution as a no-no …

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SYS Schema First Steps
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Oracle DBAs have has the luxury of their V$ variables for a long time while we MySQL DBAs pretended we were not envious. With MySQL 5.6 and 5.7 we were gifted with the PERFORMANCE_SCHEMA tables. But there is such a wealth of information in those tables that it is intimidating to plunge in to them.  Thankfully Mark Leith has given us the SYS Schema. The SYS Schema is a collection of views, functions and procedures to help MySQL administrators get insight in to MySQL Database usage.

The first step is to get a copy of the SYS SCHEMA files.
git …

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Shinguz: failed MySQL DDL commands and Galera replication
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Taxonomy upgrade extras: galerareplicationDDLTOIRSU

We have recently seen a case where the following command was executed on a Galera Cluster node:

SQL> GRANT SUPER ON userdb.* TO root@127.0.0.111;
ERROR 1221 (HY000): Incorrect usage of DB GRANT and GLOBAL PRIVILEGES



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MySQL 5.6 Transportable Tablespaces best practices
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In MySQL 5.6 Oracle introduced a Transportable Tablespace feature (copying tablespaces to another server) and Percona Server adopted it for partial backups which means you can now take individual database or table backups and your destination server can be a vanilla MySQL server. Moreover, since Percona Server 5.6, innodb_import_table_from_xtrabackup is obsolete as Percona Server also implemented …

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MySQL message subscription system
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Introducing MQ system based on MySQL (canal + roma)
Using this system to subscribe message between different platforms.

View this PDF roma_system
Also download this PDF from slideshare

10 Newer Entries Showing entries 31 to 40 of 33583 10 Older Entries

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