… data in the largest table. You can find the individual SSB query definitions in my …datadir=/mnt/mysql56/data basedir=/usr/local/mysql socket=/var/lib/mysql/mysql.sock user=justin innodb_buffer_pool_…size=32M innodb_buffer_pool_instances=16 metadata_locks_hash_instances=32 table_open_cache_instances=…
Post: MySQL 5.6 Compatible Percona Toolkit 2.2 Released
March 25, 2013 By 2 Comments
…_lock_wait_timeout because that now conflicts, or is at least confused with, lock_wait_timeout (introduced in MySQL 5.5) for metadata locks…, binary, and tcpdump), so you shouldn’t have a problem finding queries to run and compare. pt-query-digest is simpler… a standard (http) connection. pt-stalk and pt-mysql-summary have built-in MySQL options No more “pt-stalk — -h db1 -u…
Post: Open Source, the MySQL market (and TokuDB in particular)
May 10, 2013 By 13 Comments
…, you provide the following benefits to your customers: No vendor lock-in. And this is significant. Customers often choose products that… all buzz, but you can find some grains of truth in the article “Dead database walking: MySQL‘s creator on why the… that article: “In principle, anyone who has an interest in MySQL and MariaDB surviving should contact the MariaDB foundation and ask…
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
… a six-hour tutorial about Percona XtraDB Cluster (PXC) for MySQL. I actually had more material than I covered (by design… existence of a replication feedback mechanism, unlike anything you find in standard async MySQL replication. It is my belief that the lack… node by simply by running “FLUSH TABLES WITH READ LOCK“, or perhaps by “LOCK TABLE”, in which case flow control will kick…
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
… Now let’s see what kind of goodies does Helgrind find on MySQL server. Let’s take a recent 5.1 bzr… 0x4C2A1CB: pthread_mutex_lock (hg_intercepts.c:496) ==9090== by 0x74A32E: show_status_array(THD*, char const*, st_mysql_show_var*, enum… Valeriy Kravchuk has confirmed it by finding another (related) lock order violation: between LOCK_system_variables_hash and LOCK_plugin. I have only shown…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
… block and fail with a lock wait timeout. The problem is, it can be very difficult to find the offending code so… free)”>&2 exit 1 fi host=$(mysql -ss -e ‘SELECT p.HOST FROM information_schema.innodb_lock_waits w INNER JOIN information… make them commit between iterations. And watch your server to find idle-in-transaction connections that are just sitting there doing…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
…at pt-query-digest report it is easy to find slow queries or queries which cause the large … Last_errno: 0 Killed: 0 # Query_time: 9.031233 Lock_time: 0.000086 Rows_sent: 0 Rows_examined: …are found and returned up to the top level MySQL part for processing are counted the Rows_examined remains…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 11 Comments
… be deployed, and you will not find it anywhere but in production. The pmp-check-mysql-deadlocks plugin can help you detect…-mysql-processlist plugin checks SHOW FULL PROCESSLIST for patterns that indicate similar problems to those discussed within InnoDB, but it can find… connections all trying to open or close tables can indicate LOCK_open contention. Replication is delayed or stopped. Our plugins are…
Post: How to Identify Bad Queries in MySQL
January 10, 2011 By 16 Comments
… the others from running. This could be due to internal locks, I/O starvation, or what have you. In all of… duration the query executed for, which has been available in MySQL for years. This is necessary for determining whether a group… standard MySQL) might be enough precision for finding some cases of queries blocking others, but it’s nowhere near precise enough to find…
Post: Eventual Consistency in MySQL
November 18, 2011 By 8 Comments
… in any complex database. We can find all foreign keys by querying the …: $ cat generate_foreign_key_checks.sql | mysql -N | mysql -E *************************** 1. row *************************** test.Bar.ID… so you can correct them. 1Innodb locking and Foreign Keys 2Instrumentation and the cost…
