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Displaying posts with tag: gtid (reset)
MySQL Group Replication

So MySQL's group replication came out with MySQL 5.7. Now that is has been out a little while people are starting to ask more about it.

Below is an example of how to set this up and a few pain point examples as I poked around with it.
I am using three different servers,

 Server CENTOSA

mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';
Query OK, 0 rows affected (0.02 sec)

vi my.cnf

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MySQL Support Engineer's Chronicles, Issue #10

As promised, I am trying to write one blog post in this series per week. So, even though writing about InnoDB row formats took a lot of time and efforts this weekend, I still plan to summarize my findings, questions, discussions, bugs and links I've collected over this week.

I've shared two links this week on Facebook that got a lot of comments (unlike links to my typical blog posts). The first one was to Marko Mäkelä's blog post at MariaDB.com, "

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MySQL Master High Availability and Failover: more thoughts

Some months ago, Shlomi Noach published a series about Service Discovery.  In his posts, Shlomi describes many ways for an application to find the master.  He also gives detail on how these solutions cope with failover to a slave, including their integration with Orchestrator.

This is a great series, and I recommend its reading for everybody implementing master failover, with or without

MySQL Master Replication Crash Safety Part #3: GTID

This is a follow-up post in the MySQL Master Replication Crash Safety series.  In the two previous posts, we explored the consequence of reducing durability on masters (including setting sync_binlog to a value different than 1) when slaves are using legacy file+position replication.  In this post, we cover GTID replication.  This introduces a new inconsistency scenario with a potential

MySQL Tutorial – Understanding The Seconds Behind Master Value

In a MySQL hosting replication setup, the parameter Seconds_Behind_Master (SBM), as displayed by the SHOW SLAVE STATUS command, is commonly used as an indication of the current replication lag of the slave. In this blog post, we examine how to understand and interpret this value in various situations.

Possible Values of  Seconds Behind Master

The value of SBM, as explained in the  MySQL documentation, depends on the state of the MySQL slave in general, and the states of MySQL slave SQL_THREAD and IO_THREAD in particular. While IO_THREAD connects with the master and reads the updates, SQL_THREAD applies these updates on the slave. Let’s examine the possible values of SBM during different states of the MySQL Slave.

When SBM Value is Null

  • SBM is …
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Fun with Bugs #78 - On Some Public Bugs Fixed in MySQL 5.7.25

Today I'd like to continue my tradition of ignoring MySQL 8 (after all, I can not even build 8.0.14 any more on my Ubuntu 14.04, it's not supported suddenly because of old gcc version) and, of all MySQL server versions released by Oracle this week, concentrate on bugs reported in public bugs database and fixed in the latest minor release of MySQL 5.7 branch, 5.7.25.

This time there is only one InnoDB community-reported bug fixed, Buig #87423 - "os0file.cc assertion failed 'offset > 0' in os_file_io_complete", from Vasily Nemkov. See also it's duplicate, …

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Using dbdeployer With MariaDB Server

Some time ago I've noted that one of the tools I use for testing various MySQL and MariaDB cases and to reproduce potential bugs, MySQL-Sandbox, is not updated any more. It turned out that active development switched to its port in Go called dbdeployer. You can find detailed information about dbdeployer and reasons behind developing it provided by its author, Giuseppe Maxia, here and there. See also this post at Percona blog for some quick review of its main features. One of the points of …

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Fun with Bugs #73 - On MySQL Bug Reports I am Subscribed to, Part X

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 bug reported by …
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How to Quickly Add a Node to an InnoDB Cluster or Group Replication

Quickly Add a Node to an InnoDB Cluster or Group Replication (Shutterstock)

In this blog, we’ll look at how to quickly add a node to an InnoDB Cluster or Group Replication using Percona XtraBackup.

Adding nodes to a Group Replication cluster can be easy (documented here), but it only works if the existing nodes have retained all the binary logs since the creation of the cluster. Obviously, this is possible if you create a new cluster from scratch. The nodes rotate old logs after some time, however. Technically, if the

gtid_purged

 set is non-empty, it means you will need another method to add a new node to a cluster. You also …

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How To Fix MySQL Replication After an Incompatible DDL Command

MySQL supports replicating to a slave that is one release higher. This allows us to easily upgrade our MySQL setup to a new version, by promoting the slave and pointing the application to it. However, though unsupported, there are times when the MySQL version of slave deployed is one release lower. In this scenario, if your application has been performing much better on an older version of MySQL, you would like to have a convenient option to downgrade. You can simply promote the slave to get the old performance back.

The MySQL manual says that ROW based replication can be used to replicate to a lower version, provided that no DDLs replicated are incompatible with the slave. One such incompatible command is ALTER USER which is a new feature in MySQL 5.7 and not available on 5.6. :

ALTER USER …
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