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Displaying posts with tag: MySQL 5.6 (reset)

Cloning MySQL 5.6 instances
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A tip for all those cloud users that like cloning database servers (as reported in my book Effective MySQL – Replication Techniques in Depth).

Starting with MySQL 5.6, MySQL instances have a UUID. Cloning servers to quickly create slaves will result in the following error message.

mysql> SHOW SLAVE STATUS\G
...
  Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
...

The solution is simple. Clear our the file based configuration file (located in the MySQL datadir) and restart the MySQL instance.

$ rm -f /mysql/data/auto.cnf
$ service mysql restart
Amazon RDS with MySQL 5.6 – Configuration Variables
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One longstanding complaint I have heard for the past several years, and still hear today, is that Amazon’s Relational Database Service (RDS) does not allow the configuration flexibility as running MySQL in an ec2 instance. While true, this ignores the consistent work that Amazon has done to provide access to the most important configuration variables needed to tune a MySQL instance (after all, how relevant is it for a customer to set bind_address in an RDS instance).

Let’s take a look visually:

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MySQL Security: Armoring Your Dolphin
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My colleague and teammate Ernie Souhrada will be presenting a webinar on Wednesday, August 21, 2013 at 10 a.m. PDT titled “MySQL Security: Armoring Your Dolphin.”

This is a popular topic with news breaking routinely that yet another Internet company has leaked private data of one form or another. Ernie’s webinar will be a

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Understanding max_connect_errors
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To only slightly misquote one of the greatest movies of all times:

You keep using that option.  I do not think it means what you think it means.

 

Perhaps like many users, I had certain assumptions about what max_connect_errors really does – but in looking closely as part of investigating the new PERFORMANCE_SCHEMA.HOST_CACHE table in MySQL 5.6, I learned that some very fundamental elements had escaped my notice.  I’m writing this blog post to help others who hold similar misconceptions of what this option does.

Many, if not most, MySQL DBAs are familiar with “host blocked”

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Percona Server 5.6 Webinar follow-up and Q&A
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Good news everyone! I recently presented a webinar: Percona Server 5.6: Enterprise Grade MySQL. It was also recorded so you can watch along or view the slide deck. As with all my talks, I am not simply reading the slides so it really is worth to listen to the audio rather than just glance through the slide deck.

There were a number of great questions asked which I’ll answer below:

Q: How does Stewart feel about this version of 5.6 taking into consideration “Stewart’s .20 rule?” (ref 2013 Percona Live Conference).

A: For those who aren’t familiar with it, I have a rule which I call “Stewart’s dot twenty rule” which I’ve posted a few times about on

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Spring Cleaning: Useless protocol commands
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In an earlier post, I commented on clients and utility programs which seem to no longer be useful, and opened (or referenced existing) public bug reports to deprecate and remove, where appropriate.  That effort came actually was the product of a different initiative:  I was looking for clients which might leverage the full spectrum of MySQL protocol commands in an effort to understand whether certain protocol commands are in use.  I thought I would share my observations, in the hope that we might also get feedback from others regarding usage of these commands. And even though it’s no longer spring (I started this post in April), I finally found time to finish this post.

The

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Practical P_S: Fixing gaps in GLOBAL STATUS
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Over three years ago, I noticed that there was no STATUS counter for COM_PING commands – something that is useful for ensuring proper configuration of JDBC connection pools.  Mark Leith even provided a patch, but it’s never been incorporated.  With the advances PERFORMANCE_SCHEMA makes in MySQL 5.6, that’s OK – a STATUS counter becomes somewhat redundant:

mysql> SELECT SUM(count_star) as pings
    -> FROM events_statements_summary_global_by_event_name
    -> WHERE event_name = 'statement/com/Ping';
+-------+
| pings |
+-------+
|    12 |
+-------+
1 row in set (0.02 sec)


Not only does PERFORMANCE_SCHEMA provide capabilities which mirror the STATUS

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Standalone MySQL Utilities Now GA! Includes running mysqlfailover as a daemon
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With the release of MySQL Utilities 1.3.4, the standalone (not bundled with the MySQL WorkBench GUI) package is now Generally Available and fully supported. This post will focus on a very important change (the ability to run as a daemon rather than in a terminal) to the mysqlfailover utility which allows you to build a light-weight HA database solution using MySQL Replication.

For a general overview of MySQL Utilities,

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Option prefixes deprecated
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MySQL 5.6.13 was released earlier this week, and in that release (as well as 5.5.33) the ability to use unique option prefixes was deprecated.  This is fully removed from MySQL 5.7, and I thought it might be useful to amplify the change log notes on why this was done:

Previously, program options could be specified in full or as any unambiguous prefix. For example, the --compress option could be given to mysqldump as --compr, but not as --comp because the latter is ambiguous. Option prefixes now are deprecated. They can


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Practical P_S: How idle are your connections?
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Idle connections can cause problems both at the application side, increasing the risk of connection timeouts for applications where persistent connections are used, and the server side, where resources remain allocated to idle connections.  Any application with persistent connections, such as a JDBC application using a connection pool, will have periods where connections are idle – but it’s good to know how much time is spent idle.  Too much idle time might mean connections pools configured to allow too many connections to sit idle in a connection pool, or not properly doing connection pool maintenance.

PERFORMANCE_SCHEMA in MySQL 5.6 makes it trivial to measure absolute time spent waiting.  This will show total, average

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10 Newer Entries Showing entries 61 to 70 of 181 10 Older Entries

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