… for small amount of threads. For 8 threads the 95% response time is 0.69ms. Now let me get… second. I draw boxplots, which show 25-50-75 percentiles. So there is no grow in throughput after 2 … question how does it affect MySQL performance, and I am going to run some MySQL workloads on these cards to…
Post: Computing 95 percentile in MySQL
November 28, 2008 By 5 Comments
When doing performance analyzes you often would want to see 95 percentile, 99 percentile and similar values. The “average” is the evil of… 95/99 percentile and get your logs in the table, so how to get the data if MySQL only provides you the avg: mysql… this system the 95 percentile is just over 5 sec (some 3 times more than the average) and 99% percentile is just a…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… should expect from the system. What I usually look for MySQL is performance in random reads and random writes. Sequential 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: mysql-proxy, urgh performance and scalability ?
June 9, 2009 By 27 Comments
… 1 thread). MySQL per-request statistics: min: 1.31ms avg: 1.51ms max: 5.30ms approx. 95 percentile: 1.56ms Proxy+MySQL per-request statistics: min: 2.04ms avg: 2.86ms max: 6.44ms approx. 95 percentile: 4.30ms… consider if you want to run Query Analyzer with MySQL-proxy on your MySQL Enterprise setup. There is alternative – Dormando-proxy, which…
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…
Post: What do we optimize with mk-query-digest ?
December 15, 2009 By 2 Comments
… acceptable for interactive queries. It is best to look at 95 percentile “time” rather than slowest time for the queries as there… to be optimized. It helps if batch jobs use different MySQL user compared to the web site itself as it makes…) – it is however perfectly possible to get bad performance with MySQL responsible for large portion of response time without any slow…
Post: Performance Optimization and Six Sigma
June 7, 2010 By 6 Comments
… and not acceptable. So how are doing with this in MySQL (and general Web performance management) ? Not So good. In most… 95 percentile something like 1000 transactions will give more or less stable results in most cases. If we’re looking at 99 percentile…. I believe meeting 95 percentile response time every minute of the day is a lot harder than getting 99 percentile over 24 hours…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… enable logging atomically, not just for new connections as in MySQL. This is very helpful for measurement as otherwise we might… give more importance to the times/values reported in the 95% (95th percentile) column as that gives us more accurate understanding. Now… underlying tables involved and the query execution plan used by MySQL. The end result might be that you end up limiting…
Post: Color code your performance numbers
June 2, 2010 By 4 Comments
… functions. We most likely would like to see some percentile numbers – 95 percentile or 99 percentile. The problem is computing these in SQL is… 3 seconds and anything over that will be considered unacceptable: mysql> select sum(wtime=1.0 and wtime=3.)/count(*)*100… before we get large number of yellow or red requests: mysql> select avg(if(wtime
Post: Introducing tcprstat, a TCP response time tool
August 31, 2010 By 12 Comments
…packet. For many simple protocols such as HTTP and MySQL, this is the moral equivalent of a query’s… microseconds. These are repeated for the 95th and 99th percentiles as well. Other metrics are also available. Here’s… 1 timestamp count max min avg med stddev 95_max 95_avg 95_std 99_max 99_avg 99_std …
