Tag: MySQL Replication

Feed: Planet MySQL; Author: Severalnines; Delayed replication allows a replication slave to deliberately lag behind the master by at least a specified amount of time. Before executing an event, the slave will first wait, if necessary, until the given time has passed since the event was created on the master. The result is that the slave will reflect the state of the master some time back in the past. This feature is supported since MySQL 5.6 and MariaDB 10.2.3. It can come in handy in case of accidental data deletion, and should be part of your disaster recovery plan. The ... Read More

Feed: Planet MySQL; Author: Frederic Descamps; The MySQL, MariaDB and Friends devroom was once again flooded with submissions. The committee, consisting of community members Daniël van Eeden, Art van Scheppingen, Giuseppe Maxia and Aurélien Lequoy, as well as Tom de Cooman for Percona, Vicentiu Ciorbaru for MariaDB and Nuno Carvalho for MySQL/Oracle, had the difficult job of whittling down 67 submissions into the final 17. The following sessions were selected: Session Speaker Start End Welcome Frédéric Descamps and Ian Gilfillan 10h00 10h30 Patterns and anti-patterns in OSS participation – Lessons from MySQL AB, the MariaDB Foundation, and others Zak Greant ... Read More

Feed: Planet MySQL; Author: Marcelo Altmann; PREVIOUS POST Continuing on the series of blog posts about MySQL High Availability, today we will talk about stale reads and how to overcome this issue. The Problem Stale reads is a read operation that fetches an incorrect value from a source that has not synchronized an update operation to the value (source Wiktionary). A practical scenario is when your application applies INSERT or UPDATE data to your master/writer node, and has to read it immediately after. If this particular read is served from another server in the replication/cluster topology, the data is either not ... Read More

Feed: Planet MySQL; Author: Valeriy Kravchuk; It's time to continue my review of MySQL bug reports that I considered interesting for some reason recently. I had not got any notable reaction from Oracle engineers to my previous post about recent regression bugs in MySQL 8.0.13, so probably this topic is not really that hot. In this boring post I'll just review some bugs I've subscribed to since August that are still not closed, starting from the oldest.Let me start with a couple of bug reports that remain "Open":Bug #91959 - "UBSAN: signed integer overflow in lock_update_trx_age". It's really unusual to see ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; PREVIOUS POST As per the documentation, pt-table-checksum is a tool to perform online replication consistency checks by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master. The master and each slave insert checksums into the percona.checksums table, and these are later compared for differences. It’s fairly obvious that the checksums need to be determined independently on each node, and so these inserts must be replicated as STATEMENT and not ROW. Otherwise, the slaves would just insert the same checksum as the master and not ... Read More

Feed: Planet MySQL; Author: Marco Tusa; PREVIOUS POST MySQL High Availability. Shutterstock.com In this article, we’ll look at an example of an on-premises, geographically distributed MySQL high availability solution. It’s part of a longer series on some high availability reference architecture solutions over geographically distributed areas. Part 1: Reference Architecture(s) for High Availability Solutions in Geographic Distributed Scenarios: Why Should I Care? Percona consulting’s main aim is to identify simple solutions to complex problems. We try to focus on identifying the right tool, a more efficient solution, and what can be done to make our customers’ lives easier. We believe in doing ... Read More

Feed: Planet MySQL; Author: Searce Engineering; Design A Highly Available MySQL Clusters With Orchestrator And ProxySQL In GCP — Part 2In part1, we explained how we are going to approach the HA setup. Here we can see how to install and configure Orchestrator and ProxySQL, then do the failover testing.Install and configure MySQL Replication:We need a MySQL with 4 Read replica and the 4'th replica will have a replica for it. And we must have to use GTID replication. Because once the master failover done, the remaining replicas will start replicating from the new master. Without GTID its not possible, but as an ... Read More

Feed: Severalnines. In this blog post, we are going to show you some examples of things that can go wrong in Galera - inexplicable node crashes, network splits, clusters that won’t restart and inconsistent data. We’ll take a look at the data stored in log files to diagnose the problems, and discuss how we can deal with these. This builds upon the previous post, where we looked into log files produced by Galera (error log and innobackup.* logs). We discussed how regular, “normal” activity looks like - from initialization of Galera replication to Incremental State Transfer (IST) and State Snapshot ... Read More

Feed: Severalnines. In the past four posts of the blog series, we covered deployment of clustering/replication (MySQL/Galera, MySQL Replication, MongoDB & PostgreSQL), management & monitoring of your existing databases and clusters, performance monitoring and health and in the last post, how to make your setup highly available through HAProxy and MaxScale.So now that you have your databases up and running and highly available, how do you ensure that you have backups of your data? You can use backups for multiple things: disaster recovery, to provide production data to test against development or even to provision a slave node. This last ... Read More

Feed: Severalnines. This is part 2 of our blog on how to troubleshoot Galera cluster - SST errors, and problems with network streaming. In part 1 of the blog, we covered issues ranging from node crashes to clusters that won’t restart, network splits and inconsistent data. Note that the issues described are all examples inspired from real life incidents in production environments. This is the eighteenth installment in the ‘Become a MySQL DBA’ blog series. Our previous posts in the DBA series include: Troubleshooting Galera cluster issues - part 1, Galera cluster diagnostic logs, Understanding the MySQL error log, Optimizing ... Read More