… memory it may be crashing , failing to execute queries or make operation to swap seriously slowing down. On now legacy 32bit platforms you… MySQL Server. The rest of memory is available for connections. For exampe with 8GB server you might have everything listed adding up to 6GB, so you have 2GB left for your threads. Each thread connecting to MySQL server will needs its…
Post: Using LVM for MySQL Backup and Replication Setup
August 21, 2006 By 53 Comments
… what exactly you need to do to perform backup of MySQL Database (or create slave) using LVM2 on Linux. 1) Connect to MySQL and run FLUSH TABLES WITH READ LOCK Note – this command may take a while to complete if you… closing connection. 5) Mount backup Filesystem: mount /dev/Main/dbbackup /mnt/backup 6) Copy data to backup. Normally you can skip slow query…
Post: Getting MySQL Core file on Linux
August 26, 2011 By 1 Comment
…to prevent core files to be dumped by setuid processes (and MySQL Server is most commonly ran changing user from “root” to “mysql…to connect as “gdb -p `pidof mysqld`” select “continue” and let MySQL run. If it crashes you will have process ready to…
Post: MySQL for Hosting Providers - how do they manage ?
November 28, 2008 By 15 Comments
… to host hundreds of users on single server with single MySQL server ? Well people just seems to be nice and not looking to crash MySQL…); select sleep(1); … Causes MySQL to “leak” 1MB of memory per second with no apparent good reason – no slow queries or queries in… this to happen ? Not really – you do not even need to be able to select from the table. Any user with permission to connect to MySQL Server…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to…commanual connect_…Slow_launch_threadsblogpercona.commanual slow_launch_timeblogpercona.commanual Slow_queriesblogpercona.commanual slow_query_logblogpercona.commanual slow…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… ungracefully (without closing the connection properly). This is happening 6 times every ten seconds. We need to figure out what is happening…, the slow query logs in the stock MySQL server are extremely limited, and for serious analysis it’s basically mandatory to use a… possible to use a patched binary, we can use MySQL Proxy, packet sniffing, or other techniques to get more information than the slow log…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
…_page_hash_index,btr_search_info_update_slow,btr_search_info_update,btr_cur_search_to_nth_level,btr_p cur_open…,mysql_select,handle_select,execute_sqlcom_select,mysql_execute_command,my sql_parse,dispatch_command,do_command,do_handle_one_connection,handle_one_connection…,JOIN::exec,mysql_select,handle_select,execu te_sqlcom_select,mysql_execute_command,mysql_parse,dispatch_command,do_command,do_handle_one_connection,handle…
Post: Analyzing Slow Query Table in MySQL 5.6
February 18, 2013 By 1 Comment
… of MySQL, when writing slow query information to the log table, query times and lock times are truncated to to integers: sql/log.cc, Log_to…,Refresh,Shutdown,Statistics,Processlist,Connect,Kill,Debug,Ping,Time,Delayed insert,Change user,Binlog Dump,Table Dump,Connect Out,Register Slave,Prepare…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… about Percona Server is the ability to enable logging atomically, not just for new connections as in MySQL. This is very helpful for measurement as otherwise we might not catch some long running connections. Now… and memory consuming, so ideally you would want to download the “slow query log” to another machine and run it there. Analyzing pt…
Post: Does Slow query log logs all slow queries ?
June 25, 2007 By 3 Comments
One may think one may use MySQL Slow query log to log all slow queries to catch problematic queries or for audit purposes. In fact…. I already mentioned mysql slave queries are not logged to slow query log and it looks like I was wrong connecting it just with… queries to be omitted from slow query log but the fact thread uses SET TIMESTAMP functionality. If you do this within normal connection…
