In this blog post, we’ll look at how we’ve improved wsrep-stages and related instrumentation in Percona XtraDB Cluster.

Introduction

When you execute a workload and need to find out what the given thread is working on, “SHOW PROCESSLIST” comes to the top of your mind. It is an effective way to track the thread status. We decided to improve the stages in Percona XtraDB Cluster to make “SHOW PROCESSLIST” more meaningful.

In the blog below, we will check out the different wsrep-stages and the significance associated with them.

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Running a simple insert/sysbench prepare workload. The state is stable as it mainly captures …

Daniel was tracking down what appeared to be a networking problem….

• server reported 113 (No route to host)
• However, an strace did not reveal the networking stack ever returning that.
• On the other side, IP packets were actually received.
• When confronted with mysteries like this, I get suspicious – mainly of (fellow) programmers.
• I suggested a grep through the source code, which revealed  return -EHOSTUNREACH;
• Mystery solved, which allowed us to find what was actually going on.

Lessons:

1. Don’t just believe or presume the supposed origin of an error.
2. Programmers often take shortcuts that cause grief later. I fully appreciate how the above code came about, but I still think it was wrong. Mapping a “similar” situation onto an existing …

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera 5.5.33a. This is a Stable (GA) release. See the Release Notes and Changelog for detailed information on this release and the Galera section of the MariaDB Knowledge Base for general information about Galera Cluster.

Download MariaDB Galera 5.5.33a

Release Notes …