… response time in terms 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> select count… number of rows which matches for given query type. Dividing the count by 100 we get our 1% of values and dividing by 20 5…
Post: Auditing login attempts in MySQL
December 28, 2012 By 4 Comments
…in MySQL Community so the first option to audit MySQL‘s authentication process is to get all the information we need from logs. General Query Log The…to get information about our users, the User Statistics. As with the previous options we can get the number…
Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL
June 22, 2012 By 33 Comments
…the new DROP Table in MySQL >= 5.5.23 work, I would like to mention quickly, that how drop table in MySQL < 5.5.23 used to work. When dropping the…to the table being dropped. Obviously this is going to take time which depends on the number of pages in the buffer pool at that time, and the…
Post: Is MySQL 5.6 slower than MySQL 5.5?
February 18, 2013 By 23 Comments
…in the next few weeks and months as MySQL 5.6 is starting to get…number of simple workloads I would expect to see some slowdown – MySQL 5.6 Optimizer got a lot smarter and the more plans have to…The questions I tried to answer are how much slower 5.6 is for such simple workload ? How…
Post: Joining many tables in MySQL - optimizer_search_depth
April 20, 2012 By 8 Comments
…number of tables. I was wondering if 0 is automatic selection why do we have value of 62 being default in MySQL 5.5…in join I think faster execution plan computation would be more important than backward compatibility. In MySQL 5.6 things are likely to get…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
…How to get CPU consumption per query ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql…to number of queries running will give average CPU usage per query. If you’re running Percona Server you can get the value from User Statistics *************************** 1. row…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…the ability to enable logging atomically, not just for new connections as in MySQL…The first row in the table above shows the Count of number of times this query was executed. Now let’s take a look at the values in the…
Post: MySQL Upgrade Webinar Questions Followup
June 28, 2012 By 7 Comments
…getting better in each new release. Also note the default storage engine changed to Innodb in MySQL 5.5, meaning you might need to…to have upgrade testing done in the environment which is maximally close to production. Q: How safe is it to upgrade from MySQL 5.5 to Percona Server 5.5…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
…to redo all of the benchmarks to get the numbers right. 2. I was running vmstat during one of the tests and my eye caught the spike in…to IO alignment yourself. In this case offset is correct, but file system is unaware how to…
Post: How fast can you sort data with MySQL ?
August 18, 2007 By 26 Comments
…MySQL does not optimize “get top N sorted rows” very well it takes just 2.5 times longer than full table scan to get the…rows in set (0.00 sec) Wait it is not right. We’re increasing sort_buffer_size and number…
