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Displaying posts with tag: Insight for DBAs (reset)
7 Fresh Bugs in MySQL 8.0

This blog post will look at seven bugs in MySQL 8.0.

Friday afternoon is always ideal for a quick look at the early quality of MySQL 8.0! Last Friday, I did just that.

If you haven’t heard the news yet, MySQL 8.0 DMR is available for download on!

Tools to the ready: pquery2, updated 8.0 compatible scripts in Percona-qa and some advanced regex to wade through the many cores generated by the test run. For those of you who know and use, this should mean a lot!

[09:41:50] [21492] ====== TRIAL …
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How X Plugin Works Under the Hood

In this blog post, we’ll look at what MySQL does under the hood to transform NoSQL requests to SQL (and then store them in InnoDB transactional engine) when using the X Plugin.

X Plugin allows MySQL to function as a document store. We don’t need to define any schema or use SQL language while still being a fully ACID database. Sounds like magic – but we know the only thing that magic does is make planes fly!

Alexander already wrote a blog post exploring how the X Plugin works, with some examples. In this post, I am going to show some more query examples and how they are transformed.

I have enabled the slow query …

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MySQL Default Configuration Changes between 5.6 and 5.7

In this blog post, we’ll discuss the MySQL default configuration changes between 5.6 and 5.7.

MySQL 5.7 has added a variety of new features that might excite you. However, there are also changes in the current variables that you might have overlooked. MySQL 5.7 updated nearly 40 of the defaults from 5.6. Some of the changes could severely impact your server performance, while others might go unnoticed. I’m going to go over each of the changes and what they mean.

The change that can have the largest impact on your server is likely


. My colleague, Roel Van de Paar, wrote about this impact in depth in another blog post, so I won’t go in much detail.

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Black Friday and Cyber Monday: Best Practices for Your E-Commerce Database

This blog post discusses how you can protect your e-commerce database from a high traffic disaster.

Databases power today’s e-commerce. Whether it’s listing items on your site, contacting your distributor for inventory, tracking shipments, payments, or customer data, your database must be up, running, tuned and available for your business to be successful.

There is no time that this is more important than high-volume traffic days. There are specific events that occur throughout the year (such as Black Friday, Cyber Monday, or Singles Day) that you know are going to put extra strain on your database environment. But these are the specific times that your database can’t go down – these are the days that can make or break your year!

So what can you do to guarantee that your database environment is up to the …

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Basic Housekeeping for MySQL Indexes

In this blog post, we’ll look at some of the basic housekeeping steps for MySQL indexes.

We all know that indexes can be the difference between a high-performance database and a bad/slow/painful query ride. It’s a critical part that needs deserves some housekeeping once in a while. So, what should you check? In no particular order, here are some things to look at:

1. Unused indexes

With sys schema, is pretty easy to find unused indexes: use the schema_unused_indexes view.

mysql> select * from sys.schema_unused_indexes;
| object_schema | object_name     | index_name  |
| world         | City …
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pt-online-schema-change (if misused) can’t save the day

In this blog post we’ll discuss pt-online-schema-change, and how to correctly use it.

Always use pt-osc?

Altering large tables can be still a problematic DBA task, even now after we’ve improved Online DDL features in MySQL 5.6 and 5.7. Some ALTER types are still not online, or sometimes just too expensive to execute on busy production master.

So in some cases, we may want to apply an


 first on slaves, taking them out of traffic pool one by one and bringing them back after the


 is done. In the end, we can promote one of the already altered slaves to be new master, so that the downtime/maintenance time is greatly minimized. The ex-master can be altered later, without affecting production. Of course, this method works best when the schema change is …

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Evaluating Database Compression Methods

Vadim Tkachenko and I have been working with Fractal Tree® storage engines (Fractal Tree engines are available in Percona Server for MySQL and MongoDB as TokuDB and PerconaFT, respectively). While doing so, we’ve become interested evaluating database compression methods, to see how to make compression algorithms work even better than they do currently.  

In this blog post, I will discuss what we found in our compression research.


Before we get to evaluation database compression methods, let’s review what compression properties are most relevant to databases in general. The first thing to consider is compression and decompression performance. Databases tend to be very sensitive to decompression performance, as it is often done in the “foreground” – …

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Better high availability: MySQL and Percona XtraDB Cluster with good application design

High Availability

Have you ever wondered if your application should be able to work in read-only mode? How important is that question?

MySQL seems to be the most popular database solution for web-based products. Most typical Internet application workloads consist of many reads, with usually few writes. There are exceptions of course – MMO games for instance – but often the number of reads is much bigger then writes. So when your database infrastructure looses its ability to accept writes, either because traditional MySQL replication topology lost its master or Galera cluster lost its quorum, why would you want to the application to declare total …

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Using dbsake to recover table structure from .frm files and process mysqldump output

We work on data recoveries quite often. In many cases, we recover table structures from the .frm files because there was no backup available. There is already a great blog post by my colleague Miguel Ángel Nieto about how we can recover structures from .frm files using MySQL utilities.

This works pretty well and we prefer to run mysqlfrm with the “–server” option to get all possible information from a .frm file. However, this option expects that MySQL is up and running so that mysqlfrm can spawn a new MySQL instance, and run the structure recovery there.

Recently I came across a tool that makes this job easier. The name of tool is …

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Slow query graphs using Performance Schema and Graphite

I love graphs. They just make things easier when it comes to finding patterns. I also love visibility. Having the ability to known what is going on inside the database is priceless. How about having visibility of the slow queries execution time on a graph? Let’s do it.

We’ve already described how to get query digest using performance schema. Since the MySQL server is already doing the heavy lifting for you with little-to-no overhead, this information is available practically at will. So let’s make some graphs with that data.

To accomplish this I will use the well-known tool Graphite to store and render time-series data. For those who are not familiar with Graphite, it’s actually a 3-piece tool, consisting of:

  • The …
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Showing entries 91 to 100 of 527
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