In 2017 we have welcomed many new customers into the Percona fold. It’s always interesting to find out what challenges the Percona team helped them to address and how they chose their relationship with Percona. As unbiased champions of open source database software, our consultancy, support and managed services staff apply their expertise across a wide range of technologies. Here are just a few stories from the past year.

Scaling applications on Amazon RDS the right way

Specializing in on-demand transportation services, Grab needed a high-availability, high performing database engine to serve their rapidly growing application. Grab operates in over 30 densely populated …

As we close out the holiday season, let’s look at some data that tells us how to guarantee a successful Black Friday (from a database perspective).

There are certain peak times of the year where companies worldwide hold their breath in the hope that their databases do not become overloaded or unresponsive. A large percentage of yearly profits are achieved in a matter of hours during peak events. It is critical that the database environment remains online and responsive. According to a recent survey, users will not wait more than 2.5 seconds for a site to load before navigating elsewhere. Percona has partnered with many clients over the years to ensure success during these critical events. Our goal is always to provide our clients with the most responsive, stable open-source database environments in order to meet their business needs.

First Stop: Germany …

Before we proceed, here is useful blog post  written by Peter on Hijacking Innodb Foreign Keys.

However, if you are trying to get rid of an unused Foreign Key (FK) constraint and related columns from versions older than mysql 5.6 or tables which cannot be executed with

ALTER TABLE ... ALGORITHM=INPLACE

  because of limitations mentioned here (specifically tables with 5.5 TIMESTAMP formats), you can use pt-online-schema-change  to drop such foreign keys.

For DROP FOREIGN KEY

constraint_name

  with  PT-OSC requires specifying

_constraint_name

  rather than the real

constraint_name

This post is a follow-up to my November 19 webinar, “Tips from the Trenches: A Guide to Preventing Downtime for the Over-Extended DBA,” during which I described some of the most common reasons DBAs experience avoidable downtime. The session was aimed at the “over-stretched DBA,” identified as the MySQL DBA short of time or an engineer of another discipline without the depth of the MySQL system. The over-stretched DBA may be prone to making fundamental mistakes that cause downtime through poor response time, operations that cause blocking on important data or administrative mishaps through the lack of best practice monitoring and alerting. (You can download my slides and view the recorded webinar here.)

Monitor the things
One of the aides to keeping the system up and …

MySQL table alterations can interrupt production traffic causing bad customer experience or in worst cases, loss of revenue. Not all DBAs, developers, syadmins know MySQL well enough to avoid this pitfall. DBAs usually encounter these kinds of production interruptions when working with upgrade scripts that touch both application and database or if an inexperienced admin/dev engineer perform the schema change without knowing how MySQL operates internally.

Truths
* Direct MySQL ALTER table locks for duration of change (pre-5.6)
* Online DDL in MySQL 5.6 is not always online and may incurr locks
* Even with Percona Toolkit‘s pt-online-schema-change there are several workloads that can experience blocking

Here on the Percona MySQL …

The Percona Managed Services team recently faced a somewhat peculiar client issue. We’d receive pages about their MySQL service being unreachable. However, studying the logs showed nothing out of the ordinary…. for the most part it appeared to be a normal shutdown and there was nothing in anyone’s command history nor a cron task to speak of that was suspicious.

This is one of those obscure and peculiar (read: unique) issues that triggered an old memory; I’d seen this behavior before and I had just the tool to catch the culprit in the act.

Systemtap made diagnostics of this issue possible and I can’t state enough how much of a powerful and often under-utilized tool set systemtap really is.

cat > signals.stp << EOF
probe signal.send {
if (sig_name == …

One of the tasks within Percona Remote DBA is to ensure we have reliable backups with minimal impact. To accomplish this, one of the tools our team uses is called mydumper. We use mydumper for logical backups because of several nice features. Some of them are:

• multithreaded, producing very fast backups compared to mysqldump
• almost no locking, if not using non innodb tables
• built-in compression
• separate files for each table, making it easy to restore single tables or schema, and the possibility to hardlink files reducing the space needed to keep history of backups. Also this feature give you the possibility to restore with more than one thread.

The mydumper project was started at the beginning of 2009 by …

One of the routine tasks for a DBA is renaming database schemas, and as such MySQL added a command to carry out that purpose called “RENAME DATABASE <database_name>”. However this command just made it through a few minor releases before being discontinued (from MySQL 5.1.7 to 5.1.23). Here’s a link to the reference manual regarding the command http://dev.mysql.com/doc/refman/5.1/en/rename-database.html. Vadim wrote a MySQL Performance Blog post about this a few years ago where he mentions the dangerous nature of this command – that post was appropriately headlined, “Dangerous Command.” Today we will see what are the ways in which a database schema can be renamed and which of them is the quickest.

Method 1: A …

I recently conducted a test backup of my “master-slave” setup in my VirtualBox as I was migrating from Percona Server 5.6.12 to version 5.6.13-rel61.0 with Percona XtraBackup v2.2.0 rev. 4885. However, doing the backup on my slave, I encountered this problem:

[04] Compressing and streaming ./test/checksum.ibd
[01] Compressing and streaming ./mysql/slave_master_info.ibd
Assertion "to_read % cursor->page_size == 0" failed at fil_cur.cc:293
innobackupex: Error: The xtrabackup child process has died at /usr/bin/innobackupex line 2641.

This is related to a bug posted by my colleague George  …

We’re less than a week away from Percona MySQL University at Portland, Oregon next Monday, June 17. The latest in a series of FREE one-day educational events, we are pleased to feature 10 technical talks by members of Team Percona as well as local members of the MySQL Community:

• Vadim Tkachenko, Percona co-Founder and CTO, will talk about Percona XtraDB Cluster, …