June 20, 2013

Post: Quickly finding unused indexes (and estimating their size)

… who needed to reduce their database size on disk quickly without a…name as table_name, all_indexes.index_name as index_name from all_indexes left join used_indexes using (TABLE_SCHEMA, TABLE_NAME, INDEX_NAME… for your table by simply doing: mysql> alter table mytable ENGINE=Innodb; However, this…

Post: Best kept MySQLDump Secret

…consistent backup for their Innodb tables without making database read only. In most cases it works, …from the fact how MySQL‘s Transactions work with DDL, In particular ALTER TABLE. When ALTER TABLE is … and rename such temporary table to original name. How does data visibility works in this case …

Post: InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

… simply a matter of upgrading to 5.6 and running ALTER TABLE foo ENGINE=InnoDB. In theory, yes. In practice, not… looking for someone’s full name, which I knew to be present only once in the database, and I used double quotes to group the search terms as a single phrase: With 5.5: mysql: SELECT id, full_name

Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs

… of taking a consistent backup of your MySQL databases – but did you know that you can…mysql-logs for my binary logs. I also have  the latest snapshot of the mysql-data logical volume taken namedmysql… sec) mysql> drop table salaries; — Ooops! Query OK, 0 rows affected (0.49 sec) mysql> alter table…

Post: Statement based replication with Stored Functions, Triggers and Events

…this_year does not exist’ on query. Default database: ‘test’. Query: ‘insert into t VALUES(this_year… this case we alter every event adding DISABLE ON SLAVE. ALTER EVENT even_name DISABLE ON SLAVE. … on the slave. Example: mysql> SELECT YEAR(CURDATE()) INTO @this_year; mysql> insert into t VALUES(@…

Post: How Percona does a MySQL Performance Audit

database. The first step is to find out what MySQL…_admin_commands | 255868807 | 11893 | | Com_alter_db | … | Variable_name | Value | Value | +———————————–+———————-+———————-+ |…

Post: High-Performance Click Analysis with MySQL

… log files out of the database.  The database is usually the most expensive… you from the downtime caused by ALTER TABLE — a typical reason to think…either using MySQL 5.1′s row-based replication, or in MySQL 5.0 …”flexible schemas” with tables that contain name-value pairs or something similar. The…

Post: Database problems in MySQL/PHP Applications

…$dbcon->query(“Select email from user where name=%s”,$name) – wrapper will detect query is …told by people with traditional database background. Things are different with MySQL. There are many successful …important benefits – your data becomes managable, your ALTER TABLE or OPTIMIZE TABLE now locks …

Comment: Dangerous command

…– in a directory named after the database, referenced from a .frm file in views, in various tables in the mysql database, etc. so implementing… was to help with upgrades that involve re-encoding the database name on disk. that functionality lives on as ALTER DATABASE … UPGRADE DATA DIRECTORY NAME.

Post: Finding your MySQL High-Availability solution – Replication

… is well designed and has specific database handles for read and write …MySQL, altering a table means recreating the whole table and it is a blocking operations. Alteringname imply, manages the availability of the MySQL service. A high availability solution based on MMM requires at the 2 MySQL