… causes of problems in MySQL systems. They are intentionally not generic because I wanted to focus on doing one thing with each… of status counters and variables. This is the pmp-check-mysql-status plugin, which can perform computations on status variables. By… Compute the rate of change over time for one or more counters (e.g. queries per second) The documentation contains examples of how to…
Post: Joining many tables in MySQL - optimizer_search_depth
April 20, 2012 By 6 Comments
…very good one, yet you could notice EXPLAIN itself was taking same 5 seconds, which points…per manual will chose best value automatically. Making this change I could bring optimization, and full query…the following explanation from Timour Katchaounov in MySQL mailing list archives I have some …
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
…seconds per second. Of course no system scale perfectly, so you would unlikely be able to get 16 queries per second… per query ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql#… understanding how much your queries (at least most important ones) cost you in terms …
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 8 Comments
… as the one that ships by default with many server installations) or a system administration mistake to delete one of MySQL‘s log… (Seconds_behind_master or the delay indicated by the pt-heartbeat tool, if you choose), and actual failure. The pmp-check-mysql… the incremental increase in a variable such as Queries and alert on a queries-per-second threshold. (I don’t suggest doing this; I…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 6 Comments
… work is being done in terms of requests per second. Should be easy to see on the graphs…system which queries mysql. I’ve seen monitoring updates which would add excessively expensive and frequent query on …do not be mistaken, it is not always just one issue which is responsible for everything, Quite …
Post: Is your server's performance about to degrade?
May 18, 2010 By 13 Comments
… servers running lots of queries. As a rough guide, I’m seeing this in servers running 20k queries per second and higher, lots of memory, lots of CPU cores, and most queries are running faster than one millisecond; some… done about it — and that’s where improvements to the MySQL source code are necessary. But in many cases something can…
Post: Checking for a live database connection considered harmful
May 5, 2010 By 38 Comments
…MySQL protocol level, which will increment Com_admin_commands in SHOW GLOBAL STATUS, or a trivial query…queries take longer than a millisecond or so. When you’re running 20k queries per second against your database server, an extra 20k queries per second… they grow. It’s one of those things that works…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
…the number of misses per unit of time, with the units of operations per second. The key cache miss…query of interest will accidentally get faster too, and we’ll get a treat. There is one interesting…over 10-second or 60-second intervals and compare the results to your IO system’s capabilities. MySQL …
Post: Introducing new type of benchmark
February 25, 2012 By 16 Comments
…mysql, the final result is also represents the throughput (transactions per second in sysbench; NewOrder transactions Per Minute in tpcc-mysql… are different theories, and the one which describes user’s behavior,…our target is arrival rate 2 queries per second, then exponential distribution will give …
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
… not choose the faster one? That’s what this post is about. Let’s start with the MySQL query optimizer. The optimizer tries… modern disk can do about 100 random I/O’s per second, as a rule of thumb. If you do the math… divide this by 100 I/O operations per second, and then divide that by 86400 seconds in a day, you get about 2…
