… last webinar, but did not have time to analyze it in-depth. If you try to do something like this in MySQL 5.5, you will succeed without errors or warnings: mysql> ALTER TABLE test ADD INDEX (col2); Query OK… be created-, but we will get a warning (note severity, to be exact): mysql> ALTER TABLE test ADD INDEX (col2); Query OK, 0…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars. If you missed… matching rows that you’ll get skewed results. For instance, if …. Another workaround may be to add a column to the table, … in the index. Example: WHERE (last_name, first_name) = (‘Karwin’, ‘Bill’); Q…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…sync MySQL replication? It’s actually much worse than Galera. As I illustrated in a blog post last…someone joins a group, you run a transaction that adds the relationship row to users_groups, but …state changes. retry deadlocks Now we start to get into (*gasp*) territory where your application needs …
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…+———-+————-+————————————————————-+ | 1 | 46.78110075 | ALTER TABLE test add column c char(32) default … at the last stages when its…get piled up waiting for table metadata lock bringing down the MySQL server or causing all the connections to get…
Post: Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker
November 29, 2011 By 102 Comments
…get the resource agent from here: https://github.com/y-trudeau/resource-agents/raw/master/heartbeat/mysql…policy=”ignore” \ last-lrm-refresh=”1322236006″ property $id=”mysql_replication” \ replication_info=”10.2.2.162|mysql-…t have to define this, the mysql RA will add it automatically when the first…
Post: MySQL 5.5.8 - in search of stability
January 3, 2011 By 11 Comments
… can compute this value as Log sequence number – Last checkpoint at from SHOW ENGINE INNODB STATUS. …getting the stable result of article [1], and the difference is the doublewrite area. Doublewrite activity actually adds… to be the most stable line I can get with MySQL 5.5.8. The 15-minute average…
Post: Percona Server on the Raspberry Pi: Your own MySQL Database Server for Under $80
February 25, 2013 By 10 Comments
…you have your hardware, here is how to get Percona Server for MySQL up and running: Insert the SD card into a…168.0.180 root@192.168.0.180′s password: Last login: Fri Feb 22 23:27:49 2013 from …command line If you did get a SD card which is larger then 2GB, you can add another partition using fdisk & …
Post: Product to try: MySQL/MariaDB-Galera 0.8
June 13, 2011 By 34 Comments
… setup is 3 nodes and you can add / remove nodes almost transparently. It is possible…last weeks, and from my observation, the task to setup three node cluster is much more complex than an average MySQL…this is price to pay for synchronous not-getting-behind slaves. With additional nodes, the response…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
…get CPU consumption per query ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql…operation per second which takes 4ms which adds up pretty well. We can also …3BBF3B55 (1/0%), 3BBF3B5A (1/0%)… 1753695 more # Last errno 0 # Users user # Query_time distribution # 1us # 10us…
Post: How to Identify Bad Queries in MySQL
January 10, 2011 By 16 Comments
… experience, or they add too much load to the system, or they block other queries from running This last three-part definition… duration the query executed for, which has been available in MySQL for years. This is necessary for determining whether a group… completed in a cluster. One-second granularity (what you get in standard MySQL) might be enough precision for finding some cases of…
