Ideas, releases, practical guides, and perspectives from the people building with MySQL.
In this post, the first one of a Maxscale series, I describe how to use MariaDB’s MaxScale and MySQL-utilities with MySQL Asynchronous replication.
When we talk about high availability with asynchronous replication, we always think about MHA or PRM. But if we want to transparently use the slave(s) for READs, what can we use ?
Description:
Errant transactions are a major issue when using GTID replication. Although this isn’t something new, the drawbacks are more notorious with GTID than with regular replication.
The situation where errant transaction bites you is a common DBA
task: Failover. Now that tools like MHA have
support for GTID replication (starting from 0.56
version), this protocol is becoming more popular, and so
are the issues with errant transactions. Luckily, the fix is
as simple as …
Recently, I was working on a MySQL support ticket where a customer was facing
an issue while transporting tablespace from MySQL
5.6 to MySQL 5.7.
After closely reviewing the situation, I saw that
while importing tablespace they were getting errors such as:
ERROR 1808 (HY000): Schema mismatch (Table flags don't match, server table has 0x10 and the meta-data file has 0x1)
After some research, I found that there is a similar bug reported to MySQL for this issue (https://bugs.mysql.com/bug.php?id=76142), but no solution is mentioned. I tested the scenario locally and found a solution …
[Read more]Update 2016-01-30: restarting the IO_THREAD might be considered useful in some situations (avoiding MDEV-9138). Look for "in contrast, if the IO thread was also stopped first" in MDEV-6589 for more information.
In a previous post, I listed some sequences of commands that you should not run on a MariaDB slave that is lagging and which is using the GTID protocol. Those are the following (do not
In the spirit of sharing war stories and avoiding others to do the same mistakes as I did, here are some sequences of commands that you should avoid to run on a MariaDB slave that is lagging and which is using the GTID protocol. Remember, do not run those because...
So, those bad commands are the following:
"STOP SLAVE; START SLAVE UNTIL ...;", or "STOP SLAVE; START SLAVE;" (to remove an
On Percona Live! Amsterdam 2015 we had a talk with Peter Boros about GTID replication.
Here are the slides.
In my latest series of advanced replication features, I came across several usability
issues, which I would like to recap here. For each section of
this list of requests, I make a wish list, with some general
comments.
INSTALLATIONAs the maintainer of MySQL Sandbox, a
tool that wants to facilitate the installation of …
Previous episodes:
MySQL replication in action - Part 1: GTID &
CoMySQL replication in action - Part 2 - Fan-in
topologyMySQL replication in action - Part 3 - All-masters
P2P topology
Introducing star topology.In all-masters P2P topologies, we have
seen that we have a way of deploying a topology where all nodes
are masters, and achieve better efficiency and stability than
ring topologies. That …
In the theoretical part of this series, we have seen
the basics of monitoring. In that article, though, we have barely
mentioned the new tools available in MySQL 5.7 and MariaDB 10.
Let’s start from something that has the potential of dramatically
changing replication as we know it.
Crash-safe tables and Global transaction identifiers in MySQL 5.6
and 5.7Global transaction identifiers (GTID) is a feature that
has been in my wish list for long time, since the times I was
working with the MySQL team. By the time I left Oracle, this
feature was not even in the plans.
When MySQL 5.6 was first disclosed, the biggest improvement for
replication was the introduction of crash-safe tables (see
Status persistence in …
Beware the SST
In Percona XtraDB Cluster (PXC) I often run across users who are fearful of SSTs on their clusters. I’ve always maintained that if you can’t cope with a SST, PXC may not be right for you, but that doesn’t change the fact that SSTs with multiple Terabytes of data can be quite costly.
SST, by current definition, is a full backup of a Donor to Joiner. The most popular method is Percona XtraBackup, so we’re talking about a donor node that must:
