…to use oprofile and see if there are sleep() statements). What did I see in ‘top’ … doesn’t mysql show query times in microseconds? I had to resort to Perl + Time::HiRes for timing the Infobright …-purpose” database use — there are a number of limitations (concurrency, for one) and it looks like it…
Comment: Debugging sleeping connections with MySQL
February 19, 2007 By 30 Comments
… give more detail on using strace/gdb? i have few mysql that sleep for over 1000 and.. netstat on port gives me… php/mysql guru, just a part-time sysadmin that wants to solve this problem as usually in 1-2 days mysql conn. limit gets…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… 0 MySQL thread id 8079, query id 728899 localhost root Sending data select sql_calc_found_rows * from b limit 5 Trx… tries to limit thread concurrency allowing only innodb_thread_concurrency threads to run inside Innodb kernel at the same time. If thread…. This is done by adjusting innodb_thread_sleep_delay variable. Value is specified in microseconds. mysql tables in use 1, locked 0…
Post: InnoDB thread concurrency
June 5, 2006 By 4 Comments
… not enough number of running threads. Moreover as threads sleep for certain time before entering the queue, the true number of threads… with limited innodb_thread_concurrency. This is why innodb_commit_concurrency variable was added in MySQL 5.0 innodb_commit_concurrency limits number…
Post: Gathering queries from a server with Maatkit and tcpdump
July 1, 2009 By 23 Comments
…about every bit of information about queries that mysql-proxy can, making this a viable way to…-query-digest –type=tcpdump –limit 1 tcpdump.out # 460ms user time, 30ms system time, 8.88M rss, 11.79M vsz…CREATE TABLE `dual`\G # EXPLAIN select 1 from ( select sleep(.1) from dual ) as x\G Indeed, it’s…
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
… your normal working set from OS cache. Operation Systems and MySQL Itself employs various strategies to attempt to minimize such effect… sleep between them so none of them can take too much resources for too long time. If you delete things do DELETE … LIMIT 1000 and insert sleep 10; in between. By spreading…
Comment: Why do you need many apache children ?
February 17, 2008 By 15 Comments
….conf do great harm to so many mysql connections in sleep state for so long time(wait_timeout). Original timeout was set to default (300 seconds). Some terribly slow http connection consumes timeout limit to… hour in mysql error log. After changing Timeout directive in httpd.conf, all seems to be ok. Mysql connections in sleep state only…
Post: Using LoadAvg for Performance Optimization
December 4, 2006 By 5 Comments
…in “running” state or in “uninterruptable sleep” state which typically corresponds to disk…batch job on the server with MySQL, Load Average is likely to …(table/row level locks) or other limiting factors such as innodb_thread_concurrency…up to 3-4 times more load before response time starts to suffer. …
Comment: MySQL Server Memory Usage
September 1, 2006 By 21 Comments
…handle for 32 bit? Some stats at writing time (18:37 friday) System copes fine with these ….79, 1.00, 0.95 328 processes: 326 sleeping, 2 running, 0 zombie, 0 stopped CPU states:…mysql/data log-bin=/var/log/mysql/log log-slow-queries=/var/log/mysql/slow-queries.log max_connections=650 open_files_limit…
