Showing entries 31 to 40 of 92
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: configuration (reset)
On configuring the Performance Schema

On configuring the Performance Schema

This article is a user guide about MySQL 5.6 Performance Schema configuration. As with many things, the way to approach problems may vary a lot based on systems, user experiences, or just plain opinions, so the "Your Mileage May Vary" caution applies here.

It is easy to get lost in details, and yet starting with the big picture in mind helps to understand not only how, but also more importantly why, to do things ...

The magic recipe is as follows

  • Define your goals
  • Define what to instrument
  • Define how much detail to collect
  • Provide sizing data
  • Monitor sizing problems

Define your goals
Performance instrumentation in general can be used for many different things, ranging from casual monitoring in production to debugging in development, with every flavor in …

[Read more]
Do we need a MySQL Cookbook?

The blog title says it all: Do we need a MySQL Cookbook? I tend to think so.

This seems to be something that is missing with current MySQL documentation. There is lots of information available but finding the appropriate bit can be quite tedious and it often requires looking in multiple places.

A lot of other software has such books, but for some reason MySQL seems to be missing one.

A recent example comes from a “documentation feature request” I posted today: MySQL 5.6 provides a way to “move InnoDB tables” from one server to another. There are many reasons why you may want to do it, but the documentation is currently rather sparse. A simple “example recipe” for this would be good, as would an equivalent recipe for other engines where you can do this such as MyISAM. This is just an isolated …

[Read more]
Thoughts on MySQL 5.6 new replication features

After playing a little bit with MySQL 5.6 (RC), and following closely on Giuseppe's MySQL 5.6 replication gotchas (and bugs), I was having some thoughts.

These are shared for a few reasons:

  • Maybe I didn't understand it well, and someone could correct me
  • Or I understood it well, and my input could be of service to the developers
  • Or it could be of service to the users

InnoDB tables in mysql schema

The introduction of InnoDB tables in mysql makes for crash-safe replication information: the exact replication position (master log file+pos, relay log file+pos etc.) is updated on InnoDB tables; with innodb_flush_logs_at_trx_commit=1 this means replication status is durable and consistent with server data. This is …

[Read more]
MySQL 5.6, GTID and performance_schema

Not much to add really to the bug I’ve filed here: bug#67159.

Again this GTID stuff looks good, but seems to prevent changes in the configuration of performance_schema, which I think is not appropriate, especially as P_S now has lots of extra goodies and after 5.6 will surely have even more.

Help me polish MySQL in openSUSE 12.2

If you are following news regarding openSUSE and MySQL, you probably already know, that we have both MySQL and MariaDB in openSUSE to allow users to choose what they want to use. And if these two options are not enough, we’ve got server:database repository with newest and greatest development versions of both and MySQL Cluster on to of that. I think all this is great and awesome, that we have all of that.

Now to the not so great part. Unfortunately I’m bare human, I have to eat, sleep and I have some work, some bugs that takes a lot more time that I expected, some school duties to take care of and of course openSUSE Conference to organize! So as a result of all that, I can’t polish MySQL and MariaDB as much I would love to. And on top of that, I’m not …

[Read more]
What is the proper size of InnoDB logs?

In one of my previous posts, “How to resize InnoDB logs?”, I gave the advice on how to safely change the size of transaction logs. This time, I will explain why doing it may become necessary.

A brief introduction to InnoDB transaction logs

The transaction logs handle REDO logging, which means they keep the record of all recent modifications performed by queries in any InnoDB table. But they are a lot more than just an archive of transactions. The logs play important part in the process of handling writes. When a transaction commits, InnoDB synchronously makes a note of any changes into the log, while updating the actual table files happens asynchronously and may take place much later. Each log entry is assigned a Log Sequence Number – an incremental value that always uniquely identifies a change.

[Read more]
The Problems of Managing MySQL’s Configuration

I want to keep a record of the configuration of the MySQL servers I manage. The configuration of some servers differs from others and over time the configuration may vary, partly as a result of upgrades in the mysql version or the use of the particular mysql instance, so tracking this is important.

Configuration items in MySQL can be thought of in 2 separate parts: the static configuration files which determine the behaviour of the server when it starts up (my.cnf) and the running configuration of the server in question. The latter information is usually obtained by running SHOW GLOBAL VARIABLES and SHOW SLAVE STATUS if the server is a slave.

I’d also like to compare the 2 sets of configuration so I can see if a local change has been made to the running server which is not reflected in its configuration file. I might want to correct this, or at least be aware of it.

However, collecting and …

[Read more]
PuppetConf and the state of devops

It’s been some time now that we’ve been talking about devops, the pushing together of application development and application deployment via IT operations, in the enterprise. To keep up to speed on the trend, 451 CAOS attended PuppetConf, a conference for the Puppet Labs community of IT administrators, developers and industry leaders around the open source Puppet server configuration and automation software. One thing that seems clear, given the talk about agile development and operations, cloud computing, business and culture, our definition of devops continues to be accurate.

Another consistent part of devops that also emerged at PuppetConf last week was the way it tends to introduce additional stakeholders beyond software developers and IT …

[Read more]
Useful sed / awk liners for MySQL

Listing some useful sed / awk liners to use with MySQL. I use these on occasion.

sed, awk & grep have many overlapping features. Some simple tasks can be performed by either. For example, stripping empty lines can be performed by either:

grep '.'
awk '/./'
sed '/./!d'
grep -v '^$'
awk '!/^$/'
sed '/^$/d'

It's a matter of taste & convention which tool and variation to use. So for any script I suggest, there may be many variations, possibly cleaner, shorter; feel free to comment.


The output of mysqldump is in particular useful when one wishes to make transformation on data or metadata.

  • Convert MyISAM tables to InnoDB:
mysqldump | sed -e 's/^) ENGINE=MyISAM/) …
[Read more]
Recovering a MySQL `root` password: the fourth solution

Have just read Darren Cassar’s Recovering a MySQL `root` password – Three solutions. There’s a fourth solution: using an init-file, which leads to just one restart of the database instead of two. It also avoids the security issue involved with using skip-grant-tables.

I’ve written all about it before on Dangers of skip-grant-tables.

Darren’s 1st advice (look for password ini files, scripts, etc.) is a very good one. One password that can always be looked up in files is the replication’s password.

Replication’s password is easily forgotten: you only set it once and never use it again; never script it nor manually login with. When setting up new slaves, though, you …

[Read more]
Showing entries 31 to 40 of 92
« 10 Newer Entries | 10 Older Entries »