… end up in a split-brain situation. Typically DRBD is run in combination with heartbeat or pacemaker or something similar, and… occurs. For example, if you see a large number of long-running queries in the output of SHOW PROCESSLIST that might be….frm’ ERROR: 1033 Incorrect information in file: ‘./mysql/servers.frm’ Running mysql_install_db under strace, I saw that it was…
Comment: MySQL Performance Forums
June 9, 2013 By 18 Comments
… be down. Basically I have a problem regarding long running select query. A query runs for say 300 seconds and because the resultset…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
…%– buf_page_init_for_read(dberr_t*, unsigned long, unsigned long, unsigned long, unsigned long, long, unsigned long) … 31.41% 15534570 mysqld mysqld [.] rw_lock_x… Percona Server shows much better results Configurations and how to run benchmark: [mysqld] user=root port=3306 innodb_buffer_pool_size…
Post: MySQL 5.6 Compatible Percona Toolkit 2.2 Released
March 25, 2013 By 2 Comments
…. pt-upgrade is brand-new pt-upgrade was written once long ago and not updated since. Now that we have four… received mini overhauls in 2.2 to make their run-related options (–run-time, –interval, –iterations) standard. If you hadn’t noticed… gone now: both tools run forever by default, so specify –iterations or –run-time to limit how long they run. There are more changes…
Post: Rotating MySQL slow logs safely
April 18, 2013 By 7 Comments
… a MySQL standby server hot using MySQL slow logs with long_query_time set to 0. Here are a some lessons… flushes tables in addition to logs. Flushing tables can impact running queries. Disable MySQL slow logs during rotation Flushing logs takes…/local/bin/mysql -e ‘select @@global.long_query_time into @lqt_save; set global long_query_time=2000; select sleep(2); FLUSH…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
… do not have enough space on this SSD to run this experiment that long. So there we see the strong side of… lp:~vadim-tk/sysbench/insert-roll-2, command line to run: sysbench –test=insert_roll.lua –oltp-table-size=10000 –mysql…=10 –max-requests=0 –num-threads=32 –rand-type=pareto run and InnoDB options are: [mysqld_safe] numa-interleave malloc-lib…
Post: Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
… active server of a pair. The passive server has mysqld running and replicating from the active master. In theory, failing over… for information about discarded designs and benchmarks.) First, we set long_query_time to 0 in order to log every query…-pool that will allow connection reuse. This is necessary when running a large stream of queries. Benchmarks We benchmarked with slow…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… node we can have all sorts modifications floating around as long as they don’t touch the same row. Row locks… the relationship between them. When someone joins a group, you run a transaction that adds the relationship row to users_groups… data durability isn’t as crucial. This is fine as long as you weigh both options carefully. But in Galera you…
Comment: Rotating MySQL slow logs safely
April 19, 2013 By 7 Comments
… reopened the file. 2. logrotate runs the postrotate stanza 2a. Slow logging is paused (set global long_query_time=2000;) 2b. There… are reopened (FLUSH LOGS;) 2d. Slow logging resumed (set global long_query_time=@lqt_save;)
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
… is asynchronous on all but the node the transaction is run on. It’s important to realize that Galera prevents conflicts…. A large fc_limit in this case might mean a long wait before flow control gets relaxed again. However, this was… to halt queue applying on any node by simply by running “FLUSH TABLES WITH READ LOCK”, or perhaps by “LOCK TABLE…
