… close connection MySQL can clean them up. Killing connections (or stopping related applications) and observing whenever memory usage shrinks can be… ? memory tables ? In a lot of cases you have to guess and test, you can’t get information of how much…
Post: To find the bottleneck, stop guessing and start measuring
August 4, 2008 By 8 Comments
… machine is really doing much work. Why? Maybe you guessed the network. Nope, not the network either. There… was using exactly 25% of its CPU capacity, would you guess that it had 4 CPU cores and one of them…. The way we do this is to prefer measurements to guesses. Of course, finding the problem is only part of the…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
… drive, or drive being resynced) as missing: ReadyNAS1:/# mdadm –stop /dev/md2 mdadm: stopped /dev/md2 mdadm –verbose –create /dev/md2 –chunk… such way also allows you to check if you have guessed correctly and if you created RAID wrong way you probably…
Post: Death match! EBS versus SSD price, performance, and QoS
February 21, 2011 By 54 Comments
… final zoom-in on a specific device, and I’ll stop belaboring the point. Let’s look at the performance of… 4 reads per second from that device. You can probably guess that this database server is in pretty severe trouble, waiting… EBS storage means that if the active set of data stops fitting in memory, or if a lot of transactional writes…
Post: The story of one MySQL Upgrade
October 8, 2010 By 8 Comments
… test suite we could use for validation. As you might guess in such cases some of the original authors have moved… data improperly loaded with mysqldump if there is such). We stopped 5.0 and 5.1 slave at the same position… was the time to check how read traffic behaves. We stopped both slaves at the same position again and used tcpdump…
Post: Looking at Redis
August 27, 2009 By 27 Comments
… performance will be good enough for many applications. Also nothing stops you from running many Redis instance on single server to…/map in the data types but I guess there is nothing in architecture which would stop it from being added later. Redis…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… to MySQL Server, all MySQL Security guarantees is you can stop one from seeing data you do not want one to see (or change data) but it does ensure you can stop one from overtaking the server. This will not really change… of these comes from real experiences others are just my guesses of what could break things. As you can see from…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 2
October 16, 2009 By 8 Comments
… memcached. Wow that’s shockingly fast isn’t it! I guess being completely in memory helps for this app. What… start with Tokyo Tyrant and Cabinet.   So stop in next time for part 3 of this series where… Tyrant. Wow that’s shockingly fast isn’t it! I guess being completely in memory helps for this app. What is…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
… in every record R. An adaptive hash index tries to guess where our search would end in the B-tree. To… with this feature are ease of use and requirement to “guess” how your data will compress for the whole table. Among… of TLB cache misses. huge pages along however do not stop IO pressure and OS may swap out not buffer pool…
Post: Site was down today, support and web hosting.
August 31, 2007 By 27 Comments
… we moved MySQL Performance Blog to the new server, it stopped responding. I went to the control panel and reboot the… they should get back to me quickly – as you may guess I’m yet still to get reply from them. I… than escalating the case in the system. As you may guess my blood is boiling at this point. The next joke…
