… builds the html after each run, so I find it convenient to set it up on crontab so that schema changes are…> If you’re looking for other examples you can find a more comprehensive example here. Running SchemaSpy The syntax below… a particular table Constraints – lists the explicit Foreign Key constraints in the database (this does not include constraints identified via metadata…
Post: Multicast replication in Percona XtraDB Cluster (PXC) and Galera
June 5, 2013 By
… this bandwidth constraint is to switch to multicast UDP replication in Galera. This is actually really easy to do. First, we… have wsrep_provider_options set, add it to the semicolon separated list instead of a separate line in your config. If we…_node_address setting on each node if this IP is not the default IP of the server. I could not find a…
Post: The small improvements of MySQL 5.6: Duplicate Index Detection
May 31, 2013 By Leave a Comment
… 1 row in set (0.00 sec) In previous versions of MySQL, you can create two indexes with the same columns (in the same….test’. This is deprecated and will be disallowed in a future release. 1 row in set (0.00 sec) As the message points… MySQL, for which we at Percona tend to find redundant indexes. And second, because in some cases, we may need to have…
Post: Replication in MySQL 5.6: GTIDs benefits and limitations - Part 2
May 30, 2013 By 6 Comments
…articles focused on MySQL 5.6 GTIDs. You can find part one here. Our goal will be to … event executed: s1> show slave status\G [...] Executed_Gtid_Set: 219be3a9-c3ae-11e2-b985-0800272864ba:1, 3d3871d1-c3ae-…There is a solution of course, but very poor in my opinion: look for the binlog file/position …
Post: Replication in MySQL 5.6: GTIDs benefits and limitations - Part 1
May 21, 2013 By 8 Comments
… a specific replication topology. However you should keep in mind some limitations of the current implementation. This …replication for other slaves at the same time? To find an answer to these questions, let’s create …, but only if all servers have gtid_mode set to ON. Could it be interesting to run …
Post: How to fix your PRM cluster when upgrading to RHEL/CentOS 6.4
May 29, 2013 By 2 Comments
… percona1 writer_vip (ocf::heartbeat:IPaddr2): Started percona1 Master/Slave Set: ms_MySQL [p_mysql] Masters: [ percona2 ] Slaves: [ percona3 percona1 ] [root... is not present any more 
It's still possible to find the command install crmsh (crm shell from another repository) or...): Started percona1 Master/Slave Set: ms_MySQL [p_mysql] Masters: [ percona1 ] Slaves: [ percona2 percona3 ] So if you were in maintenance mode, you…
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
… MySQL 5.6.10, both with default settings using only the InnoDB storage engine. In my testing I discovered that innodb_old… is approximately 12GB of data in the largest table. You can find the individual SSB query definitions in my previous blog post. Test… follow-up post about concurrency in another blog post in this series. Regardless, when the working set fits in memory, InnoDB almost always performs…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… about using a temporary table to store an interim result set, and then use that to ultimately produce the result you… up the row with “=” instead of “>” and be guaranteed to find exactly one match. But the tradeoff of this solution is… conclusion of my presentation today is that sometimes you find unexpected differences in performance like this, so it pays to test all…
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
… is existence of a replication feedback mechanism, unlike anything you find in standard async MySQL replication. It is my belief that the… the wsrep_provider_options global variable. gcs.fc_limit This setting controls when flow control engages. Simply speaking, if the wsrep…. An example configuration tuning flow control in a master/slave cluster might be: mysql> set global wsrep_provider_options=”gcs.fc_limit…
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
… define in MySQL, we’ll see that it’s defined as 4096. This, however, is not the true limit. To find out… each field (but not the table) An interval in UNIREG speak is a set of strings that are the options for ENUM…)+2) (bytes) + length of all comments (in bytes) + length of all intervals (for ENUM, SET) in bytes. If you use that as a…
