… benchmark for example – it defines the guidance for response time as ninety five percentile response time, which is just two sigma in sigma notation… and Maatkit also use 95% response time (probably inherited from these industry standards). Sometimes we use 99% response time as a guidance but this…
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… very frequently and had very unstable performance: during the time data was collected, response time varied from 50µs to 1s. When I ran… of the response time, and not only having low response times sometimes. In this case, a stable 160ms response time was preferred to a response time ranging from…
Comment: Introducing new type of benchmark
March 11, 2012 By 16 Comments
… processing time P – it’s the reciprocal of the max system throughput (1/TPS in the case of a database). The response time of the system under load is R = P + L + Q, where is Q is the average time a request… represent the user’s workload – both the max throughput and response time are going to change together when the workload mix changes…
Post: Why message queues and offline processing are so important
August 10, 2010 By 3 Comments
… where load cannot be increased without degrading response time below acceptable levels. Setting and meeting your response time goal should always be your primary…) your response time objectives in order to have more tasks completed per unit of time. It is much easier to relax response time objectives if…
Post: Understanding Performance Optimization Terminology
March 2, 2009 By Leave a Comment
… down to two important metrics – response time also sometimes called latency and throughput also called capacity. Response time applies to even single user and… same time. The response time is the most important aspect of performance because when we define system capacity we also define conditions on response time…
Post: Percona XtraDB Cluster Feature 2: Multi-Master replication
January 19, 2012 By 22 Comments
… the local node. That is response time of COMMIT consist of several parts: Network roundtrip Certification time Local applying Please note that applying… nodes does not affect the response time of COMMIT, as it happens in the background after the response on certification. The two important…
Post: What do we optimize with mk-query-digest ?
December 15, 2009 By 2 Comments
… overload, row level locks, table locks all could cause query response time to be unreasonable. If Slowest query is not interactive query… of these query sets. If you are looking for improving response time of particular transaction/user interaction you really have to look… perfectly possible to get bad performance with MySQL responsible for large portion of response time without any slow queries. We’ve seen pages…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
… invalidated. If a frequently executed or expensive query is invalidated, response time will be significantly impacted. The invalidation frequency is controlled by… the problem (mostly likely because the response time goes up due to increased concurrency) but the time to compute the contents is low…
Comment: Beware of MyISAM Key Cache mutex contention
August 14, 2008 By 10 Comments
…_tables=133. 1. Two threads and one table, the average response time is about 143ms Thread1: access table t1 Thread2: access table… average response time is about 137ms. Thread1: access table t1 and table t2 alternately 4. One thread and one table, the average response time… from t1, thread2 read data from innodb table test, the response time for thread1 is also about 80ms. Thread1: access table t1…
Post: btrfs - probably not ready yet
May 22, 2012 By 17 Comments
… is also less stable. Response time: The same happens with response time. Actually 95% response time is about 10x worse with btrfs. And response time, timeline: We can see that btrfs is very far from providing a stable response time…
