The latest from the MySQL community

Recovering to a particular time in the past is called Point-In-Time Recovery (PITR). With PITR you can rollback unwanted DELETE without WHERE clause or any other harmful command.

PITR with Percona XtraBackup is pretty straightforward and perfectly described in the user manual. You need to restore the data from the backup, then apply all binary logs created or updated after the backup was taken, but skip harmful event(s).

However, if your data set is large you may want to recover only the affected database or table. This is possible but you need to be smart when filtering events from the binary log. In this post, I will show how to perform such a partial recovery using Percona XtraBackup, …

It is no secret that compute and storage costs are the main drivers of cloud bills. Migration of data from the legacy data center to the cloud looks appealing at first as it significantly reduces capital expense (CapEx) and keeps operational expenses (OpEx) under control. But once you see the bill, the lift and shift project does not look that promising anymore. See Percona’s recent open source survey which shows that many organizations saw an unexpected growth around cloud and data.

Storage growth is an organic process for the expanding business: more customers store more data, and more data needs more backups and disaster recovery storage for low RTO.

Today, the Percona Innovation Team, which is part of the Engineering organization, is proud to announce a new feature – High Compression. With this feature enabled, …

MySQL installation security is something that should be on the  mind of every MySQL DBA. While we have discussed how you should take care of your MySQL security as a whole (take a look at some of our previous posts, specifically the MySQL security series Part One and Part Two), we haven’t  discussed specific security-related issues, including  those issues related to privileges. We do that here.

What are Privileges in MySQL?

Privileges in MySQL can be granted to accounts. If you grant account privileges in MySQL, you determine which operations the account can perform. Privileges can be granted to either databases or database objects (tables, indexes, views etc.) Privileges can also be dynamic or static. Static privileges …

For MySQL, MyISAM and InnoDB storage engines are very popular. Currently, we are mostly using InnoDB engines for high reliability and high performance. Apart from those engines, we also have some other alternative engines and they have some nice features in them. In this blog, I am going to explain some of those engines, which I have listed below. 

• FEDERATED Storage Engine
• Merge or MRG_MyISAM Engine
• Blackhole Engine
• CSV Engine

FEDERATED Storage Engine Overview:

• FEDERATED Storage Engine allows you to access the data remotely without replication and cluster technologies. 
• Using the FEDERATED tables, you can scale your server load. Queries for the given table will be sent over the network to another MySQL instance. In this case, to scale the DB, you can use many MySQL instances without changing the application code.
• FEDERATED tables …

CodeIgniter’s Query Builder ORM has class methods for nearly any kind of database access/operation you can think of. In this post, I’ll cover some of the available methods for retrieving aggregate-level query results. The examples in this post map out Query Builder method chaining to produce results you would get from a raw MySQL query. Continue reading to see more…

Image by Clker-Free-Vector-Images from Pixabay

Self-Promotion:

If you enjoy the content written here, by …

Starting a long time ago, we wanted to reproduce workload in a non-production environment, and there were different attempts to achieve that goal (Query Playback is just one of them). But there is another point of view, where you need to write your own workload to do so.

Both Have Pros and Cons

Reproduce Workload:

Pros:

• Simple to implement
• Ready to go

Cons:

• Need to rebuild the environment each time

Custom Scripts:

Pros:

• Possible to have a more realistic workload
• You can reuse the environment
• You can use Sysbench that allows you to change …

The idea of ACID transactions are a basic feature of SQL’s individual Data Manipulation Language (DML) commands, like the INSERT, UPDATE, and DELETE statements. Transactions across two or more tables are a natural extension of ACID compliance features provided by DML commands. However, they require a structured programming approach, like a store procedure or like API implemented in an imperative language.

Surprisingly, transaction management wasn’t covered well in Alan Beaulieu’s Learning SQL because he only provided pseudo code logic. While I thought troubleshoot some broken MySQL SQL/PSM logic would be a good learning experience for students, it wasn’t. So, I wrote this sample code to show how to achieve an all or nothing transaction across four tables.

The code for this example on transaction management lets you perform the important tasks necessary to effect transaction …

A question has cropped up recently: how does one install Galera Cluster 4 with MySQL 8 on Ubuntu 20.04 LTS (Focal Fossa)? This quick guide will get you started.

Install 3 Galera Cluster nodes with the base OS being Ubuntu 20.04. Remember to run apt update and apt upgrade.

Once this is done, edit: /etc/apt/sources.list.d/galera.list and add the following lines:

deb https://releases.galeracluster.com/galera-4/ubuntu focal main
deb https://releases.galeracluster.com/mysql-wsrep-8.0/ubuntu focal main

Once that is done, don’t forget to also pin the preference to the Galera Cluster repository. To do this, edit: /etc/apt/preferences.d/galera.pref and have it read:

# Prefer the Codership repository
Package: *
Pin: origin releases.galeracluster.com
Pin-Priority: 1001

Once you are done, run apt update yet again. Now you are ready to install Galera Cluster 4 with MySQL 8, just by …

Recently one of our customers ran into an issue, wherein a bad actor(code) from the application had made the wrong update to 16 M records of a critical table in the database, causing the entire production process to go down. The application Team was able to find the bad actor and block it, our Remote DBA was involved in the Data Recovery/Rollback.

Here I would like to discuss possible recovery methods for the above said scenario

Delayed Slave:

A simple and effective way to recover is by using a delayed slave, RDS started supporting this feature from version 5.6.40 and 5.7.22 i.e., you can induce a SQL thread delay-interval for applying the writes to a slave, detailed implementation is covered in our blog here. It’s …

»If at all possible, we build databases so that the working set of the database fits into memory.« What does that even mean?

Working Set

In computer science, the “Working Set” of a program is the set of things it will be accessing in the near future. Because computer science has not yet solved looking into the future, we are looking at the set of things we accessed most recently and hope for The Best™.

The Best™ here being that our future access pattern is very similar to our most recent past access pattern.

Why Memory Matters

In MySQL, the “things we access” in the Working Set definition is RAM, Memory.

We do care, because memory is fast. How fast is fast?

Images from …