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Displaying posts with tag: Replication (reset)
Fun with Bugs #41 - Bugs Fixed in MySQL 5.7.11

I've just noted that Oracle had released new versions of MySQL on February 5, 2016 formally, so while these days I am mostly thinking about the ways to do support properly, remembering my colleagues and trying to understand some of RocksDB internals, it's time to postpone all these and write about bugs again. This time about some of the public bug reports from MySQL Community and Oracle engineers that were fixed by Oracle in MySQL 5.7.11.

As usual, I'll try to mention who had reported a bug and who verified it, as I think that names matter in MySQL world. I'll concentrate mostly on InnoDB, replication and optimizer bug reports, trying to highlight regressions clearly.

As usual, I prefer to start with InnoDB bugs:

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MySQL Support People - Percona Support

I planned to continue this series of posts with the one about MySQL Support engineers who joined us in Oracle while I was working there, but based on recent events in my life I'd prefer to postpone it and move directly to the team I worked for during last 3+ years, Percona Support Team.

Disclamer: In the list below I still try to pay attention to public contribution by each of engineers mentioned to MySQL Community, mostly in a form of bug reports. This is not the only way they contributed, but I have to stick to this format in current series of posts. I also base my comments mostly on my memory and quick search of public sources of information, so I may be mistaking about the roles, time periods and other details. Please, inform me if you think there is something to fix.

So, here is the list of my former colleagues who formed the best MySQL Support team in the industry in 2013-2015 while working with me in …

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Extend MySQL Master HA (MHA) capabilities with MHA Helper

I have used many tools starting with MMM to be able to manage MySQL replication clusters. Some of the tools require additional tools and complex HA solutions such as Pacemaker and Corosync, or Zookeeper. While other tools do not do the failover well which leaves the slaves in an inconsistent state, MMM would be an example. And I must say that of all the tools I love MySQL Master HA (MHA) the most. MHA is a great tool to manage MySQL replication clusters for the purpose of HA. The most important thing about MHA is that it tries to take...

The post Extend MySQL Master HA (MHA) capabilities with MHA Helper appeared first on ovais.tariq.

Why log_slave_updates is a bad default

In a recent post the MySQL product managers asked the community for feedback about proposed new defaults. One of the proposals is to make log-slave-updates on by default.

There are other important options that require some debate. They all look reasonable to me. This one, instead, which implies funnelling the replication events in a slave to its binary log, is questionable.

Let's start for the reason why it is a good idea. The scenario in which it makes sense is when you want a slave to be a master of one or more slaves. This is a common scenario in many cases where you need …

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MySQL Support People - The Next Generation

My first post in this series caused quite an active discussion on Facebook. Readers correctly noted some mistakes in dates and missing names in the list. I've corrected some of the mistakes already and will correct some others later. What was also noted is that initially support for MySQL was provided by developers (this is really important, we'll get back to this later), and of them many had never even got a title of Support engineer. Of those who had not I listed only Monty...

I just want to explain why I made these mistakes and/or why I (intentionally) had not listed developers etc. First of all, I based my post on my memories (so I could be also wrong about start dates and many details) and that's why I could not …

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MySQL Replication Defaults After 5.7

The default or “out of the box” experience is simply the experience for most people, so it’s critically important for us to ensure that the default configuration offers a good experience for the vast majority of cases. This is always a challenge, due to the matrix of factors involved–hardware configurations, software stacks, application use cases, etc.–but it’s most certainly a worthy endeavor.…

Better high availability: MySQL and Percona XtraDB Cluster with good application design

High Availability

Have you ever wondered if your application should be able to work in read-only mode? How important is that question?

MySQL seems to be the most popular database solution for web-based products. Most typical Internet application workloads consist of many reads, with usually few writes. There are exceptions of course – MMO games for instance – but often the number of reads is much bigger then writes. So when your database infrastructure looses its ability to accept writes, either because traditional MySQL replication topology lost its master or Galera cluster lost its quorum, why would you want to the application to declare total …

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Fun with Bugs #40 - Bugs fixed in MySQL 5.7.10

MySQL 5.7.10, the first release after MySQL 5.7 GA announcement, appeared almost a week ago. It's interesting to check what bugs reported by MySQL Community were fixed in this version, hence this post (that had to wait during the weekdays busy with usual support work). As usual, I'll concentrate mostly on InnoDB, replication and optimizer-related bug fixes and highlight names of those who reported and verified each bug.

Let's start with InnoDB. The following bugs reported by MySQL Community users were fixed:

  • Bug #78623 - "Small tablespaces with BLOBs take up to 80 times more space in 5.7 than in 5.6". This serious regression was reported by my colleague Laurynas Biveinis and verified by Umesh well before 5.7.9 …
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MySQL HA Solution … We have it or not ?

Data is the most important asset any organization has especially those who belongs to web, mobile, social, enterprise and cloud applications.

Availability refers to the ability to cope with, and if necessary recover from, failures on the host, including failures of MySQL, the operating system, or the hardware and maintenance activity that may otherwise cause downtime.

Because each application has different operational and availability requirements, MySQL offers a range of certified and supported solutions, delivering the appropriate levels of High Availability (HA). 

Factors to consider for HA Solution: 

  • Operational Capabilities
  • Budgetary Constraints
  • The level of availability required (In terms of Time)
  • The type of application being deployed
    • Mission critical services …
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How Lost connection to MySQL and Slave I/O thread: Failed reading log event are related ?

I am a MySQL DBA role as usual check the problems and seek a solution.
On one of the production host (MySQL v5.1.53), I started getting errors in this series:

[Note] Slave I/O thread: Failed reading log event, reconnecting to retry, log 'binlog.000942' at postion 45042
[ERROR] Error reading packet from server: Lost connection to MySQL server during query ( server_errno=2013)
[Note] Slave I/O thread: Failed reading log event, reconnecting to retry, log 'binlog.000928' at postition
[ERROR] Error reading packet from server: Lost connection to MySQL server during query ( server_errno=2013)

Some expert says you should increase the slave_net_timeout and some says to check value of  relay_log_space_limit but it is default already

slave_net_timeout = 3600
relay_log_space_limit = 0 (unlimited) 
max_allowed_packet = 128MB

I can see no heavy …

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