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MySQL 5.7 multi-source replication revealed!

Why Multi source replication is required?

MySQL has limitation of not allowing to replicate multiple DB’s from different master host on a single slave. MySQL replication had a limitation, fixed with this new release, that said that one slave could have only one master. That is a limiting factor when we are designing our replication environment. There were some “hacks” to make it work, but now there is an official way.

What is multisource replication?
MySQL Multi-Source Replication enables a replication slave to receive transactions from multiple sources simultaneously. Multi-source replication can be used to back up multiple servers to a single server, to merge table shards, and consolidate data from multiple servers to a single server. Multi-source replication does not implement any conflict detection or resolution when applying the transactions, and those tasks are left to the …

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MySQL Replication has stopped

Hi,

I think most of the DBAs experience this error in their weekly, monthly todo list. Each one follows different approach, I would like to share some tips here:

  1. You should first execute “Show Slave Status;” and check the output, analyze it. Whether SQL thread has stopped or I/O thread has stopped and check respective error , It should be either SQL error or I/O error, based on that take next step.

I/O thread has stopped:

  1. Check that you can reach the master host from slave hostby using ping or traceroute/tracert to reach the host.
  2. Connect to Master host and check whether “Replication thread” is connected.
  3. There are multiple thread state involved, you need to take action based on thread state –  …
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Become a MySQL DBA blog series - Live Migration using MySQL Replication

Migrating your database to a new datacenter can be a high-risk and time-consuming process. A database contains state, and can be much harder to migrate as compared to web servers, queues or cache servers. 

In this blog post, we will give you some tips on how to migrate your data from one service provider to another. The process is somewhat similar to our previous post on how to upgrade MySQL, but there are a couple of important differences. 
 
This is the seventh installment in the ‘Become a MySQL DBA’ blog series. Our previous posts in the DBA series include Database Upgrades, …

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In search of cleanliness : the elusive quiet installation



UPDATE: Almost solved! See at the end.

A clean installation of a database server is one where everything goes according to the expectations. It used to be easy: you only had to do what the manual says, and, presto! you would see your database server installed and ready to use. If something went wrong, you got one or more error messages that informed you of what needs to be fixed.

Sometimes, rarely, it happened that you got also a warning message, telling you that while the installation was successful, you could improve it by fine tuning this and that. No big deal.

Gone are those times. A clean installation nowadays is a much harder exercise, if not impossible. Let’s give it a try using MySQL 5.7.7.



Attempt #1 using mysql_install_db
The first error you could do when using a new version of MySQL is assuming that basic operations are …

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Comment on NDB 7.4 & SYS schema: When getting locks, detecting the guilty SQL & o.s.pid. by NDB 7.4 & SYS schema: When getting locks, detecting the guilty SQL & o.s.pid. | MySQL

[…] PlanetMySQL Voting: Vote UP / Vote DOWN Full article:NDB 7.4 & SYS schema: When getting locks, detecting the guilty SQL & o.s.pid. […]

Velocity EU: Amsterdam

VividCortex is sponsoring and exhibiting at Velcoity EU in Amsterdam October 28 - 30th. Stop by our booth to get a free product demo and see how we can revolutionize your database monitoring.

Baron Schwartz will also be speaking on Probabilistically Sampling A Stream Of Events With A Sketch.

Click here for more details and registration.

Velocity EU: Amsterdam

VividCortex is sponsoring and exhibiting at Velcoity EU in Amsterdam October 28 - 30th. Stop by our booth to get a free product demo and see how we can revolutionize your database monitoring.

Baron Schwartz will also be speaking on Probabilistically Sampling A Stream Of Events With A Sketch.

Click here for more details and registration.

VividCortex Live Demo

Have you been considering VividCortex but putting off a free trial? Are you a user who wants to get the most of the product? Are you a huge fan who simply wants to hear the brains behind the product give you the inside scoop?

Join us on Tuesday, September 15 at 2 p.m. ET (6 p.m. GMT), for a live walk through of VividCortex on production systems from our CEO, Baron Schwartz. He will use the product to demonstrate the following:

  • Using our top queries feature to quickly find queries that need attention
  • Finding and diagnosing stalls with Adaptive Fault Detection
  • Comparing queries before and after code deployments, to find workload changes
  • Understanding how your databases and queries are driving CPU, I/O and other operating system work
[Read more]
VividCortex Live Demo

Have you been considering VividCortex but putting off a free trial? Are you a user who wants to get the most of the product? Are you a huge fan who simply wants to hear the brains behind the product give you the inside scoop?

Join us on Tuesday, September 15 at 2 p.m. ET (6 p.m. GMT), for a live walk through of VividCortex on production systems from our CEO, Baron Schwartz. He will use the product to demonstrate the following:

  • Using our top queries feature to quickly find queries that need attention
  • Finding and diagnosing stalls with Adaptive Fault Detection
  • Comparing queries before and after code deployments, to find workload changes
  • Understanding how your databases and queries are driving CPU, I/O and other operating system work
[Read more]
MYSQL_HISTFILE and .mysql_history

The MySQL manual says:
"mysql Logging
On Unix, the mysql client logs statements executed interactively to a history file. By default, this file is named .mysql_history in your home directory. To specify a different file, set the value of the MYSQL_HISTFILE environment variable."
The trouble with that is: it doesn't tell you what you don't need to know. So I'll tell you.

Heritage

The history-file concept that MySQL and MariaDB are following is indeed "on Unix" and specifically is like the GNU History Library. There is a dependence on external libraries, Readline or …

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