Deadlock on FromDual GmbH

InnoDB Deadlock on SELECT? Not possible! Or Is It?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 25 Nov 2023 16:58:41 +0000

Translated by deepl.com

Introduction

Two points in advance:

A deadlock is a state in which two different transactions are no longer able to continue working because each transaction holds a lock that the other transaction would need. Because both transactions are now waiting for the other transaction to release their locks, neither transaction will release their respective locks. And that would last forever. To avoid this, the MariaDB instance intervenes and kills the transaction that has done less work. The application then receives a deadlock error message of this type:

MariaDB Deadlocks

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 11 Jan 2022 15:18:03 +0000

We get ever and ever again customer requests concerning Deadlocks. First of all, Deadlocks are usually an application problem, not a database problem! The database itself manifests the application problem with the following message which is sent to the application as an error:

innodb_deadlock_detect - Rather Hands off!

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 23 Mar 2020 11:24:15 +0000

Recently we had a new customer who has had from time to time massive database problems which he did not understand. When we reviewed the MySQL configuration file (my.cnf) we found, that this customer had disabled the InnoDB Deadlock detection (innodb_deadlock_detect).

InnoDB Deadlock detected

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 16 Jul 2015 20:10:36 +0000

You got an InnoDB Deadlock. Please talk to your development department to fix this problem. Deadlocks are an application problem!

Logging Galera Cluster conflicts

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 11 Apr 2015 12:30:54 +0000

We typically suggest our customers to use our MySQL/Galera Cluster my.cnf configuration template to avoid MySQL configuration and performance problems.

Deadlocks, indexing and Primary Key's

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 16 Aug 2012 10:51:40 +0000

Recently a customer has shown up with some deadlocks occurring frequently. They were of the following type (I have shortened the output a bit):