…. Percona Server 5.5 outperforms MySQL in about 2x times. Both MySQL 5.5.30 and MySQL 5.6.11 demonstrate notable drops… BUG#67808. For MySQL 5.6.11 top mutexes is &buf_pool->mutex,&new_index->lock. I profiled 5.6.11 in this IO bound scenario with the perf – see profile below: # Overhead Samples Command…
Post: High-load problems? Investigate them with 'pt-query-digest'
April 23, 2013 By 2 Comments
… think is a little known goodie from Percona Toolkit for MySQL called pt-query-digest. One customer was suffering from periods… ran that by pt-query-digest –type rawlog –report-format profile, to get just the ranking of queries. To my luck… issues. If you regularly work with MySQL databases, getting familiar with Percona Toolkit for MySQL will let you do more work, in…
Post: Webinar: SQL Query Patterns, Optimized
May 20, 2013 By Leave a Comment
… use MySQL 5.6 built-in methods to analyze them for optimal query efficiency. The discussion will cover optimizer reports, query profiling…
Post: Profiling MySQL Memory Usage With Valgrind Massif
January 9, 2013 By 3 Comments
… memory profile slowly growing overtime, indicating a possible memory bug. Whatever the reason, there is a simple but powerful way to profile MySQL… get a debug build of mysqld to use for memory profiling purposes: Download the appropriate debuginfo packages (these may not be…) 0x728DAA: Log_event::read_log_event(st_io_cache*, st_mysql_mutex*, Format_description_log_event const*) (in /usr/local/percona…
Post: How to convert MySQL's SHOW PROFILES into a real profile
February 20, 2012 By 12 Comments
SHOW PROFILES shows how much time MySQL spends in various phases of query execution, but it isn’t a full-featured profile. By… profile the “nicer_but_slower_film_list” included with the Sakila sample database to demonstrate: mysql> SET profiling=1; mysql> pager cat > /dev/null mysql… query consumed 0.18 seconds. Where did the time go? mysql> SHOW PROFILE FOR QUERY 1; +———————-+———-+ | Status | Duration | +———————-+———-+ | starting | 0.000032 | | checking…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…prior to MySQL 5.5.3 Metadata Locking behavior prior to MySQL 5.5.3 Prior to MySQL …locks. Let’s see the profiling information for this query: session10 > show profile for query 11; +——————————–+———-+ | Status | Duration | +——————————–+———-+ | …
Post: Profiling MySQL stored routines
January 19, 2009 By 4 Comments
…’s SHOW PROFILE patch – which is included in all Community tree based Percona MySQL builds since it is part of MySQL community version… show you how this works: mysql> set profiling=1; Query OK, 0 rows affected (0.00 sec) mysql> SELECT whatstheweatherlike(3); +———————————————————–+ | whatstheweatherlike(3…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… referring to the amazing MySQL manual, especially the option and variable reference table. …_stmt_countblogpercona.commanual print_defaultsblogpercona.commanual profilingblogpercona.commanual profiling_history_sizeblogpercona.commanual protocol_versionblogpercona.commanual proxy_userblogpercona…
Post: Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
… it without side load. Setting up 2 MySQL Servers side by side (for example with MySQL Sandbox) can especially be helpful. Once… whenever internal operation is different, you can also check SHOW PROFILE to see where differences are. Running query in the loop and getting o_profile sample can also be a good idea. If you found…
Post: Three ways that the poor man's profiler can hurt MySQL
December 2, 2011 By 19 Comments
… technique of using GDB as a profiler has become a key tool in helping us analyze MySQL when customers are having trouble… they can be. Of course, I’m really waiting for MySQL 5.6 and the improved Performance Schema that will be…
