May 25, 2012

Post: Ultimate MySQL variable and status reference list

…the amazing MySQL manual, especially the option and variable …Com_release_savepointblogpercona.commanual Com_rename_tableblogpercona.commanual Com_rename_userblogpercona.commanual Com_…Com_show_collationsblogpercona.commanual Com_show_column_typesblogpercona.commanual Com_show_contributorsblogpercona….

Post: Hijacking Innodb Foreign Keys

… all columns whenever they have changed or not: mysql> set foreign_key_checks=1; Query OK, 0 rows affected (0.00 sec) mysql… foreign key conditions (have column child table is referencing and have it of proper type and indexed): mysql> set foreign_key_checks… affected (0.00 sec) mysql> alter table parent rename parentx; Query OK, 0 rows affected (0.05 sec) mysql> drop table parentx; Query…

Post: Percona Server 5.5.10 (Release Candidate)

… beta release 5.5.8-20.0: New Features Added columns ROWS_EXAMINED, ROWS_SENT, and ROWS_READ to table PROCESSLIST… was renamed to innodb_current_row_locks. (Yasufumi Kinoshita) Old system variable innodb_enable_unsafe_group_commit was deleted. The existing MySQL variable innodb_support_xa can be used instead. (Yasufumi Kinoshita) Old system variable log_warnings_silence was renamed to log…

Post: Flexviews - part 3 - improving query performance using materialized views

… new contents of the view with the old contents (using RENAME TABLE) which means that the view remains available for querying… customers nearly instantly. Note that every MV gets a special column `mview$pk` which is an auto_increment BIGINT surrogate key… useful, simply ignore this column. It is used to prevent wide innodb primary keys on the MV. mysql> select mview$pk as…

Post: Implementing efficient counters with MySQL

… them into special counter table, having say “id” and “counter” columns. Using separate table for updates already solves the problem in… you rather use existing solutions you can use memcache + another mysql instance (or simply the database which is not replicated) to… tables insert into one and process and truncate another. MySQL offers atomic RENAME TABLE call which can be used to swap two…

Post: Percona Server and XtraBackup weekly news, March 12th

… for Debian Squeeze. We’re enhancing the PROCESSLIST to include columns for rows examined, sent, and read. This can be useful… status, several command-line options and configuration variables will be renamed. We did not always choose good names for variables and…

Post: Improved InnoDB fast index creation

… is used: mysql> SET profiling=1; Query OK, 0 rows affected (0.00 sec) mysql> ALTER TABLE t ADD COLUMN v VARCHAR(1… examples I’m extending the VARCHAR column to trigger table rebuilds without affecting the table size. mysql> SET expand_fast_index_creation… to tmp table | 18.083490 | | restoring secondary keys | 17.824109 | | rename result table | 0.162041 | | end | 0.000008 | | Waiting for query…

Post: XtraDB storage engine release 1.0.6-9

… dump and restore innodb_buffer_pool Fixed bugs: Bug#488315: rename columns and add unique index cause serious inconsistent with mysqld Bug… repo the upgrade becomes as easy as yum update MySQL-server-percona MySQL-client-percona The latest source code of XtraDB, including… bugs found on Bugs in Percona XtraDB Storage Engine for MySQL. For general questions use our Pecona-discussions group, and for…

Comment: MySQL Server Memory Usage

… ’0′ ‘Com_purge_before_date’, ’0′ ‘Com_rename_table’, ’0′ ‘Com_repair’, ’0′ ‘Com_…2′ ‘Com_show_collations’, ’176788′ ‘Com_show_column_types’, ’0′ ‘Com_show_create_db’, …mysql.sock pid-file=/var/run/mysql/mysql.pid datadir=/db/disk2/mysql/data log-bin=/var/log/mysql/log log-slow-queries=/var/log/mysql

Comment: Derived Tables and Views Performance

… syntax was for programming brevity – it’s easier to rename the output columns from the big inner query using the outer query… much smarter insertion of the sub-query’s grouping clauses. MySQL needs quite a bit of real-world tuning to make…