Are you planning an upgrade for your Percona XtraDB Cluster (PXC)? Upgrading to PXC 8.0 can be a smooth process, but sometimes challenges arise that require careful troubleshooting. In this…
The post How to fix Percona XtraDB Cluster 8.0 Upgrade issues first appeared on Change Is Inevitable.
Recently, I was working on a very unfortunate case that revolved around diverging clusters, data loss, missing important log errors, and forcing commands on Percona XtraDB Cluster (PXC). Even though PXC tries its best to explain what happens in the error log, I can vouch that it can be missed or overlooked when you do not know what to expect.
This blog post is a warning tale, an invitation to try yourself and break stuff (not in production, right?).
TLDR:
Do you know right away what happened when
seeing this log?
2023-06-22T08:23:29.003334Z 0 [ERROR] [MY-000000] [Galera] gcs/src/gcs_group.cpp:group_post_state_exchange():433: Reversing history: 171 -> 44, this member has applied 127 more events than the primary component.Data loss is possible. Must abort.
Demonstration
Using the …
[Read more]Introduction When executing an entity query (e.g. JPQL, HQL or Criteria API), you can use any SQL function without having to register it as long as the function is passed directly to the WHERE clause of the underlying SQL statement. However, if the SQL function is used in the SELECT clause, and Hibernate has not … Continue reading The best way to use SQL functions in JPQL or Criteria API queries with JPA and Hibernate →
The post The best way to use SQL functions in JPQL or Criteria API queries with JPA and Hibernate appeared first on Vlad Mihalcea.
CentOS 7 Systemd issue with Percona Cluster is that SST fails to sync the nodes, unable to join cluster group and giving the misleading broken pipe 32 SIG errors.
The post How to Resolve Systemd Issue with Percona XtraDB Cluster on CentOS 7 appeared first on Datavail.
January 27, 2015 By Severalnines
Unlike standard MySQL server and MySQL Cluster, the way to start a MySQL/MariaDB Galera Cluster is a bit different. Galera requires you to start a node in a cluster as a reference point, before the remaining nodes are able to join and form the cluster. This process is known as cluster bootstrap. Bootstrapping is an initial step to introduce a database node as primary component, before others see it as a reference point to sync up data.
How does it work?
When Galera starts with the bootstrap command on a node, that particular node will reach Primary state (check the value of wsrep_cluster_status). The remaining nodes will just require a normal start command and they will automatically look for existing Primary Component (PC) in the cluster and join to form a cluster. Data synchronization then happens through either incremental state transfer (IST) or …
[Read more]Since Ruby on Rails 4.2 has just been released, perhaps now is a good time to review creating a shiny new Rails project. It’s not often I get to create a new project from scratch, but it’s Christmas and I’ve got a bit of downtime — and an itch I’d like to scratch! So, let’s get started.
I’m aiming to build a wee project that keeps track of OmniFocus perspectives. I’ve noticed that people are sharing their perspectives as screenshots and descriptions, in tweets and blog posts. Wouldn’t it be awesome if there was a one-stop-shop for everybody’s perspectives?
A couple of early decisions in terms of the basic starting point:
Just a quick note to say that the site has been updated to a new theme which is based on the super awesome Twitter Bootstrap UI framework. To make life easier, since this site is also using WordPress at the core, I’ve made use of the WordPress Bootstrap plugin which allows for very simple integration. However, that wasn’t enough because the Bootstrap plugin comes with rather basic and boring generic styles; so I added the plugin for Google Font support and then modified the CSS accordingly.
You will also notice that the site is undergoing some reorganization of categories and content tags. This should help clean up search results as well as general information sorting. I’ve removed the sidebar widget for category listings in favor …
[Read more]Engine Yard acquires Orchestra. Red Hat considers NoSQL move. And more.
# Engine Yard announced a definitive agreement to acquire Orchestra, bringing PHP expertise to the Engine Yard platform.
# Red Hat’s CEO indicated the company is interested in a NoSQL or Hadoop acquisition.
# Gluster announced Apache Hadoop compatibility in the next GlusterFS release.
# Microsoft signed an agreement with China Standard Software Co (CS2C) to …
[Read more]
Warning... what follows is a murky mess.
It's filed as MySQL bug#43398 (verified!) but it's triggered by
cPanel doing evil.
Scenario....Start a mysql server, as normal
Then run mysql_install_db (as root, like you would when you first
install MySQL)
See a new binlog file get created, with ownership/group root!Of
course you generally wouldn't run mysql_install_db while a server
is running, but there's nothing to prevent you (or something
else) from doing so!
--bootstrap just shouldn't initialise binlog, then there wouldn't
be a issue.
cPanel runs mysql_install_db in its automatic upgrade scripts
(dangerous already, automatically upgrading MySQL Server on a
system!), it's run every night on cPanel systems even if no
upgrade is done, and it behaves exactly as described above. It
then chowns the binlog files to mysql:mysql which is of course …