… to the timestamp when the query executed, not merely the duration the query executed for, which has been available in MySQL for years. This is… mk-query-digest do to this missing analytical step. I have done it many times with simple awk scripts and various statistical measures…
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
…query_time is in microseconds and you can set it for example to 300000 which is 0.3s! # Query_time: 0.503016 Lock_time… MySQL will not write into slow log any queries executed…query execution that information is written into the log instead the above statistics. The full slow log entry for a query…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…000002 | | statistics | 0.000005 | | preparing | 0.000006 | | executing | 0.000001 | | Sorting result | 0.000002 | | Sending data | 0.000040 | | end | 0.000003 | | query end…was using MySQL version < 5.5 as the datastore. There was another interesting case this time with how Active MQ uses MySQL when…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
…query execution times into the slow log. Originally MySQL database offered a second time resolution and also a 2 second minimum for the query…, query_plan, innodb] msl patch currently can log three types of information: query timings, execution plan details and InnoDB engine per-query statistics. …
Post: Find unused indexes
June 30, 2012 By Leave a Comment
…duplicate indexes. This time we’ll …mysql. After some runs we can start to analyze the information on INDEX_STATISTICS table. mysql> SELECT * FROM INDEX_STATISTICS…query log. The concept is easy to understand. pt-index-usage reads the slow query log and execute every query with EXPLAIN to ask MySQL…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… is a very limited use for the statistics from which the ratio is derived (but…waste of time! The Oracle folks arrived at this conclusion a long time before the MySQL world…query‘s execution time. Alas, that correlation fools us into thinking it’s a cause, and we optimize-by-surrogate-measure a time…
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… time (about 160ms). Of course, I wanted to know more about how MySQL executes this query. …| 0.000013 | | statistics | 0.000075 | | preparing | 0.000016 | | executing | 0.000003 | | Sending data | 0.162272 | | end | 0.000008 | | query end…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… queries in odd statuses, like “statistics“, I know something weird is going on, and I look deeper. I also look at the queries… the top 10 most expensive queries, in total execution time. By the way, the slow query logs in the stock MySQL server are extremely limited… show the query and the information mysqlsla outputs about it (execution times, etc), the EXPLAIN plan, and the desired modifications to the query or…
Post: Profiling MySQL stored routines
January 19, 2009 By 4 Comments
…statistics available for this query SELECT whatstheweatherlike(5); Not overly useful for query optimization, is it? Well, I can still aggregate the slow query…queries are being executed. This is where Jeremy’s SHOW PROFILE patch – which is included in all Community tree based Percona MySQL…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
…query execution. The reason is – MySQL does not really have the special “plan generating” step, instead plan is generated as a part of query execution… you can use SHOW STATUS “Handler” statistics to see if number of operations … MyISAM. EXPLAIN may take long time In MySQL 5.0 with addition of greedy…
