…, key_buffer_size etc, you have reasonable amount of connections but yet MySQL takes much more memory than you would expect, causing… | grep mysqld >> ps.log sleep 60 done Check for Table Cache Related Allocations There are cases when MySQL will allocate a lot… max_packet_size per connection) are all connection buffers and so if you close connection MySQL can clean them up. Killing connections (or stopping related…
Post: Debugging sleeping connections with MySQL
February 8, 2007 By 28 Comments
… can find which connections does this process have. Here you can see it has couple of memcached connections. Few MySQL connections (to the same host, which if usually bad idea) and connection to some external web… happening with the process are not only helpful to debug sleeping connections with MySQL but many other cases when you see web application…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…/tcpdumps/`date +%s`-tcpdump & mysql -e ‘show innodb status\Gshow full processlist’ > /root/tcpdumps/`date +%s`-innodbstatus pid=$! sleep 30 kill ${pid} fi… iterations. And watch your server to find idle-in-transaction connections that are just sitting there doing nothing, and kill them…
Post: Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2
May 3, 2011 By 13 Comments
…=80 innodb_file_format=barracuda innodb_file_per_table max_connections=2000 table_cache=2000 Percona Server 5.1 Results For… replacement to proper future 5.6 tuning. MySQL 5.6.2 Results With Purge Sleeps Removed I’ve made a tiny change… purge sleeps is not enough to solve them. However, MySQL 5.6.2 is experimental code and I am sure that next MySQL…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… amazing MySQL manual, especially the option and …Compressionblogpercona.commanual concurrent_insertblogpercona.commanual connect_timeoutblogpercona.commanual Connectionsblogpercona.commanual …thread_concurrencyblogpercona.commanual innodb_thread_sleep_delayblogpercona.commanual Innodb_truncated_…
Post: Impact of the number of idle connections in MySQL
December 17, 2010 By 20 Comments
… to work with many customers having large number of connections opened in MySQL and although I told them this was not optimal… idle connections” php ./make_conn.php $numconn & cat dbt2.sql | mysql -h 10.2.2.129 -u root dbt2 sleep 120 ./run_mysql.sh… idle connections” php ./make_conn.php $numconn & cat dbt2.sql | mysql -h 10.2.2.129 -u root dbt2 sleep 120 ./run_mysql.sh…
Post: Apache PHP MySQL and Runaway Scripts
May 20, 2008 By 20 Comments
… sometimes which is obviously the problem – they take Apache Slot, MySQL Connection and other resources. I had discussion today who was thinking… long time. For simplicity I did not use MySQL, but other system call – sleep() which has similar behavior for sake of experiment… do some cleanup work – for example you can open another MySQL connection to kill the query which was running (otherwise query may…
Post: MySQL for Hosting Providers - how do they manage ?
November 28, 2008 By 15 Comments
…(“a”,1000000); select sleep(1); SET @a10:=repeat(“a”,1000000); select sleep(1); SET @a11:=repeat(“a”,1000000); select sleep(1); SET @a12:=repeat(“a”,1000000); select sleep(1); SET @a13:=repeat(“a”,1000000); select sleep(1); … Causes MySQL to “leak… to select from the table. Any user with permission to connect to MySQL Server can crash it.
Post: A recovery trivia or how to recover from a lost ibdata1 file
June 3, 2011 By 7 Comments
… disk space and good internet connectivity, I fired up an Ubuntu 10.04 EC2 instance, installed MySQL and provided the customer the…_TABLENAME.ibd /var/lib/mysql/recover/ chown mysql.mysql /var/lib/mysql/recover/$CURRENT_TABLENAME.ibd sleep 1 echo “importing tablespace” mysql -u root -e “alter…
Comment: Apache PHP MySQL and Runaway Scripts
May 21, 2008 By 20 Comments
… something like scripts or MySQL calls and does not output anything to the browser neither automatic termination not connection_aborted() check seems… the server will know that the client is there. The MySQL SLEEP function gives me thoughts about possible SQL Injection attack for… inject SLEEP(99999999) (choose your number) and disconnect. Doing it till there are no more web processes/threads, or the MySQL connections will…
