'Replication' Tag

  • The mystery of MySQL 5.6 excessive buffer pool flushing

    April 20, 2014

    I'm experimenting with upgrading to MySQL 5.6 and am experiencing an unexplained increase in disk I/O utilization. After discussing this with several people I'm publishing in the hope that someone has an enlightenment on this. We have a few dozens servers in a normal replication topology. On this particular replication topology we've already evaluated that […]

  • "Anemomaster": DML visibility. Your must-do for tomorrow

    April 18, 2014

    Here's our take of master DML query monitoring at Outbrain (presented April 2014). It took a half-day to code, implement, automate and deploy, and within the first hour of work we managed to catch multiple ill-doing services and scripts. You might want to try this out for yourself. What's this about? What queries do you […]

  • The "once and for all" SHOW SLAVE STATUS log files & positions explained

    March 6, 2014

    True, GTID is upon us whether via MySQL 5.6 or Tungsten Replicator (and wasn't it in Google Patches since 2009?). But some of us are still using standard replication with MySQL 5.5, and the "what's with all these binary log files and positions" question is ever erupting. The output of SHOW SLAVE STATUS confuses people […]

  • Seconds_behind_master vs. Absolute slave lag

    January 24, 2014

    I am unable to bring myself to trust the Seconds_behind_master value on SHOW SLAVE STATUS. Even with MySQL 5.5's CHANGE MASTER TO ... MASTER_HEARTBEAT_PERIOD (good thing, applied when no traffic goes from master to slave) it's easy and common to find fluctuations in┬áSeconds_behind_master value. And, when sampled by your favourite monitoring tool, this often leads […]

  • Thoughts on MySQL 5.6 new replication features

    October 15, 2012

    After playing a little bit with MySQL 5.6 (RC), and following closely on Giuseppe's MySQL 5.6 replication gotchas (and bugs), I was having some thoughts. These are shared for a few reasons: Maybe I didn't understand it well, and someone could correct me Or I understood it well, and my input could be of service […]

  • MySQL 5.6 new features: the user's perspective

    October 5, 2012

    This is a yet-another compilation of the new MySQL 5.6 feature set. It is not a complete drill down. This list reflects what I believe to be the interesting new features user and usability -wise. For example, I won't be listing InnoDB's split of kernel mutex. I'm assuming it can have a great impact on […]

  • Notes on row based replication

    July 4, 2012

    MySQL's Row Based Replication (RBR) succeeds (though not replaces) Statement Based Replication (SBR), as of version 5.1. Anyone who is familiar with replication data drift -- the unexplained growing data difference between master & slave -- might wish to look into row based replication. On multiple servers I'm handling the change to RBR has eliminated […]

  • Auto caching INFORMATION_SCHEMA tables: seeking input

    March 8, 2012

    The short version I have it all working. It's kind of magic. But there are issues, and I'm not sure it should even exist, and am looking for input. The long version In Auto caching tables I presented with a hack which allows getting cached or fresh results via a simple SELECT queries. The drive […]

  • Problems with MMM for MySQL

    May 16, 2011

    I recently encountered troubling issues with MMM for MySQL deployments, leading me to the decision to cease using it on production. At the very same day I started writing about it, Baron published What's wrong with MMM?. I wish to present the problems I encountered and the reasons I find MMM is flawed. In a […]

  • Impressions from MySQL conf 2011, part III: BoF Replication

    April 19, 2011

    This post continues my impressions from some of the talks I've been to. I'll dedicate this post to a single session. Wednesday BoF: Replication, Lars Thalmann, Mat Keep (Oracle) Lars Thallman presented the MySQL 5.5 replication features, as well as the expected 5.6 features. Among other features, one could notice parallel replication, binlog checksums, sub-second […]

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