Recently, one of our support customers faced this: “[ERROR] mysqld: Sort aborted: Server shutdown in progress.” At first it would appear this occurred because of a mysql restart (i.e. the MySQL server restarted and the query got killed during the stopping of mysql). However, while debugging this problem I found no evidence of a MySQL server restart – which proves that what’s “apparent” is not always the case, so this error message was a bit misleading. Check this bug report for further details http://bugs.mysql.com/bug.php?id=18256 (it was reported back in 2006).

I found that there are two possible reasons for this error: Either the MySQL server restarts during execution of the query, or the query got killed forcefully during execution which utilizes the …

While troubleshooting deadlocks for a customer, I came around an interesting situation involving InnoDB gap locks. For a non-INSERT write operation where the WHERE clause does not match any row, I expected there should’ve been no locks to be held by the transaction, but I was wrong. Let’s take a look at this table and and example UPDATE.

mysql> SHOW CREATE TABLE preferences \G
*************************** 1. row ***************************
       Table: preferences
Create Table: CREATE TABLE `preferences` (
  `numericId` int(10) unsigned NOT NULL,
  `receiveNotifications` tinyint(1) DEFAULT NULL,
  PRIMARY KEY (`numericId`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
mysql> BEGIN;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT COUNT(*) FROM preferences;
+----------+
| COUNT(*) |
+----------+
|        0 |
+----------+
1 row in set …

We have always received quite few questions here at Percona Support on how to avoid the dreaded “Too many connections” error, as well as what is the recommended value for max_connections. So, in this article I will try to cover best possible answers to these questions so others can mitigate similar kinds of issues.

My colleague Aurimas wrote a wonderful post some time back about changing max_connections value via GDB when MySQL server is running to get rid of the “Too many connections” error without restarting MySQL. You can check here for details.

By default 151 is the …

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of them needs to be properly configured to provide details on what is going on in our MySQL instances. And setting up one of these monitoring solutions is neither quick nor trivial (well, maybe with the exception of Ganglia).

MySQL Workbench provides …

We receive this question about the ibdata1 file in MySQL very often in Percona Support.

The panic starts when the monitoring server sends an alert about the storage of the MySQL server – saying that the disk is about to get filled.

After some research you realize that most of the disk space is used by the InnoDB’s shared tablespace ibdata1. You have innodb_file_per_table enabled, so the question is:

What is stored in ibdata1?

When you have innodb_file_per_table enabled, the tables are stored in their own tablespace but the shared tablespace is still used to store other InnoDB’s internal …

Today we’re celebrating Percona’s 7th anniversary.  A lot has changed in these past 7 years – we have grown from a two-person outfit focused exclusively on consulting to a 100-person company with teammates in 22 different countries and 18 different states, now providing Support, Consulting, RemoteDBA, Server Development and Training services.

We also made our mark in open source software development, creating some of the most popular …

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, …