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Displaying posts with tag: MySQL 101 (reset)
Percona Live Open Source Database Conference 2017 Slides and Videos Available

The slides and videos from the Percona Live Open Source Database Conference 2017 are available for viewing and download. The videos and slides cover the keynotes, breakout sessions and MySQL and MongoDB 101 sessions.

To view slides, go to the Percona Live agenda, and select the talk you want slides for from the schedule, and click through to the talk web page. The slides are available below the talk description. There is also a page with all the slides that is searchable by topic, talk title, speaker, company or keywords.

To view videos, go to the …

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MySQL, –i-am-a-dummy!

In this blog post, we’ll look at how “operator error” can cause serious problems (like the one we saw last week with AWS), and how to avoid them in MySQL using

--i-am-a-dummy

.

Recently, AWS had some serious downtime in their East region, which they explained as the consequence of a bad deployment. It seems like most of the Internet was affected in one way or another. Some on Twitter dubbed it “S3 Dependency Awareness Day.”

Since the outage, many companies (especially Amazon!) are reviewing their production access and deployment procedures. It would be a lie if I claimed I’ve never made a mistake in production. In fact, I would be afraid of working with someone who claims to have never made a mistake in a production environment.

Making a mistake or two is how you learn to have a full …

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used_columns: EXPLAIN FORMAT=JSON tells when you should use covered indexes

In the “MySQL Query tuning 101” video, Alexander Rubin provides an excellent example of when to use a covered index. On slide 25, he takes the query

select name from City where CountryCode = ’USA’ and District = ’Alaska’ and population > 10000

 and adds the index

cov1(CountryCode, District, population, name)

 on table

City

. With Alex’s query tuning experience, making the right index decision is simple – but what about us mere mortals? If a query is more complicated, or simply uses more than one table, how do we know what to do? Maintaining …

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Why base64-output=DECODE-ROWS does not print row events in MySQL binary logs

Lately I saw many cases when users specified option

--base64-output=DECODE-ROWS

  to print out a statement representation of row events in MySQL binary logs just to get nothing. Reason for this is obvious: option

--base64-output=DECODE-ROWS

  does not convert row events into its string representation, this is job of option

--verbose

. But why users mix these two options so often? This blog post is result of my investigations.

There are already two great blog posts about printing row events on the Percona blog: “Debugging problems with row based replication” by Justin Swanhart and “ …

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How to obtain the MySQL version from an FRM file

I recently helped a customer figure out why a minor version MySQL upgrade was indicating that some tables needed to be rebuilt. The mysql_upgrade program should be run for every upgrade, no matter how big or small the version difference is, but when only the minor version changes, I would normally not expect it to require tables to be rebuilt.

Turns out some of their tables were still marked with an older MySQL version, which could mean a few things… most likely that something went wrong with a previous upgrade, or that the tables were copied from a server with an older version.

In cases like this, did you know there is a fast, safe and simple way to check the version associated with a table? You can do this by reading the FRM file, following the format specification found here.

If you look at that page, you’ll see that the …

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Keep your MySQL data in sync when using Tungsten Replicator

MySQL replication isn’t perfect and sometimes our data gets out of sync, either by a failure in replication or human intervention. We are all familiar with Percona Toolkit’s pt-table-checksum and pt-table-sync to help us check and fix data inconsistencies – but imagine the following scenario where we mix regular replication with the Tungsten Replicator:

We have regular replication going from master (db1) to 4 slaves (db2, db3, db4 and db5), but also we find that db3 is also master of db4 and db5 using Tungsten replication for 1 database called test. This setup is currently working this way because it was deployed some time ago when multi-source replication was not possible using regular MySQL replication. This is now a working feature in …

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Staying ahead of MySQL operational problems at Percona Live

I’ve started my long journey from Florianópolis, Brazil, to Santa Clara, California and I type this words while waiting for a connection flight. Next Wednesday, Daniel Guzmán Burgos and I will be presenting in the Percona Live MySQL Conference and Expo (PLMCE).

I’m so excited with the new MySQL 101 program that has been added to this year’s event! Along the years I’ve been working as a Support Engineer at Percona I’ve heard two very distinct types of comments amongst others from some people, customers and community in general, about PLMCE:

1) That they went and it was awesome but they found it hard to follow as most of the …

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Introducing ‘MySQL 101,’ a 2-day intensive educational track at Percona Live this April 15-16

Talking with Percona Live attendees last year I heard a couple of common themes. First, people told me that there is a lot of great advanced content at Percona Live but there is not much for people just starting to learn the ropes with MySQL. Second, they would like us to find a way to make such basic content less expensive.

I’m pleased to say we’re able to accommodate both of these wishes this year at Percona Live! We have created a two-day intensive track called “MySQL 101” that runs April 15-16. MySQL 101 is designed for developers, system administrators and DBAs familiar with other databases but not with MySQL. And of course it’s ideal for anyone else who would like to expand their professional experience to include MySQL. The sessions are designed to lay a solid foundation on many aspects of MySQL development, design and …

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MySQL 101: Monitor Disk I/O with pt-diskstats

Here on the Percona Support team we often ask customers to retrieve disk stats to monitor disk IO and to measure block devices iops and latency. There are a number of tools available to monitor IO on Linux. iostat is one of the popular tools and Percona Toolkit, which is free, contains the pt-diskstats tool for this purpose. The pt-diskstats tool is similar to iostat but it’s more interactive and contains extended information. pt-diskstats reports current disk activity and shows the statistics for the last second (which by …

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MySQL 101 - Replication

So far we've looked at many aspects of MySQL, not in any great depth, but hopefully with enough information to get you started and whet your appetite for more.  Now we start to look into areas that aren't in the basic tutorials.

Replication is the technology that allows data to be stored on multiple servers. Typically this is used in "scale out" applications.  "Scale out" is used in contrast to "Scale up" where to scale a solution you buy a bigger box to run it on, where "scale out" means you buy more boxes.  Each has its benefits and drawbacks, with the usual benefit of scale out being that you get more bang for your buck.

The way replication works in MySQL is pretty simple.  One server is identified as the master, and writes every transaction to a file, the binary log.  Other servers (and there may be many) act as slaves and request information from the master. The slave keeps track of where it got up to …

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