… can take a look at some vmstat data to see what‘s actually happening on the system during all these various… entirely sure why that’s the case or at what point the performance is going to level off since these tests were…=pareto \ –forced-shutdown=1 –max-time=7200 –max-requests=0 –percentile=95 \ –mysql-user=root –mysql-socket=/tmp/mysql.sock –mysql-table…
Post: Computing 95 percentile in MySQL
November 28, 2008 By 5 Comments
… analyzes you often would want to see 95 percentile, 99 percentile and similar values. The “average” is the evil of performance optimization and often… for this system the 95 percentile is just over 5 sec (some 3 times more than the average) and 99% percentile is just a bit… numbers (it is not rare to see 99 percentile to be order of magnitude different from the average) and this is what you really…
Post: What do we optimize with mk-query-digest ?
December 15, 2009 By 2 Comments
… wait for 30 seconds which is typically not acceptable for interactive queries. It is best to look at 95 percentile “time” rather than slowest… it makes it easier to remove such queries from analyzes. What is Important to mention neither of these two query types really… to understanding what causes performance issues. If you have slow queries from interactive application it is true somebody is suffering (though it is unclear…
Post: Performance Optimization and Six Sigma
June 7, 2010 By 6 Comments
… believe meeting 95 percentile response time every minute of the day is a lot harder than getting 99 percentile over 24 hours. It is worth… 99 percentile over 5 minutes to graph response time stability. This is still very far from the confidence manufacturing uses. This is also what is…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… you quite a lot of what you should expect from the system. What I usually look for MySQL is performance in random reads…: min: 0.0001s avg: 0.0001s max: 0.0086s approx. 95 percentile: 0.0001s Threads fairness: events (avg/stddev): 773835.0000/0… avg: 0.0027s max: 0.0112s approx. 95 percentile: 0.0030s So we get about 3ms 95 percentile request time – not bad – all request…
Post: Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
… delay. At this point I remembered there is one more test I can run. What is if I put side load on DPE3…: min: 0.68ms avg: 0.88ms max: 306.80ms approx. 95 percentile: 0.94ms …. We can see quite respectful performance with longest….76ms approx. 95 percentile: 0.97ms As we see there is a stall in update for 50+ second, again while certification is happening. So…
Post: Color code your performance numbers
June 2, 2010 By 4 Comments
… what is easily computed using built in aggregate functions. We most likely would like to see some percentile numbers – 95 percentile or 99 percentile. The problem is computing these in SQL is ugly and resource consuming. There is however a simple…
Post: Virtualization and IO Modes = Extra Complexity
March 21, 2011 By 12 Comments
…: min: 0.04ms avg: 0.06ms max: 0.34ms approx. 95 percentile: 0.06ms Threads fairness: events (avg/stddev): 1343.0000/0…: min: 0.10ms avg: 1.11ms max: 259.69ms approx. 95 percentile: 5.31ms Threads fairness: events (avg/stddev): 33900.0000/0… can be sure the system is lying about write completion if we’re using O_DIRECT IO What is my take away on…
Post: mysql-proxy, urgh performance and scalability ?
June 9, 2009 By 44 Comments
… logical first choice. The obvious question which come in mind is what performance penalty we have using mysql-proxy, version 0.7….30ms approx. 95 percentile: 1.56ms Proxy+MySQL per-request statistics: min: 2.04ms avg: 2.86ms max: 6.44ms approx. 95 percentile: 4… Analyzer with MySQL-proxy on your MySQL Enterprise setup. There is alternative – Dormando-proxy, which I want to try also, but…
Post: Introducing tcprstat, a TCP response time tool
August 31, 2010 By 13 Comments
… about your TCP traffic. What is this good for? In a nutshell, it is a lightweight way to measure …microseconds. These are repeated for the 95th and 99th percentiles as well. Other metrics are also available. Here’…1 timestamp count max min avg med stddev 95_max 95_avg 95_std 99_max 99_avg 99_std …
