… works. MyISAM tables with latin1 encoding. Tried: ALTER TABLE CONVERT TO CHARACTER SET utf8; Does nothing except changes table/column encodings, but no actual content changes. So.. After this mysql thinks my table is…
Comment: Give feedback on a pt-online-schema-change update
March 23, 2012 By 2 Comments
… this, are there plans for future change ? – Column names in quotes – as we have reserved words as column names, it will be good to have the col name in quotes inside the osc, which will allow altering a table… to be dynamically changed via a file. will this also handle the part of rolling forward of changes of a table in chunks…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By Leave a Comment
… sec) mysql> drop table salaries; — Ooops! Query OK, 0 rows affected (0.49 sec) mysql> alter table employees add column age smallint unsigned not… OK, 300024 rows affected (6.51 sec) Rows matched: 300024 Changed: 300024 Warnings: 0 With the last snapshot I have above… is when you are planning to execute a long running ALTER or server upgrade, this method can be good quick rollback…
Post: Should you name indexes while doing ALTER TABLE ?
May 28, 2008 By 10 Comments
… set (0.00 sec) Such automatically table generated names are not really helpful for multiple column indexes – you can’t easily see…> alter table t1 add key(i); Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> alter table t1… run ALTER TABLE on the SLAVE server to check things out and when run it again on the master to apply changes to…
Post: AUTO_INCREMENT and MERGE TABLES
September 11, 2008 By Leave a Comment
…columns inserting into Merge Table and in the last table…ALTER TABLE for underlying tables. Unlike with TRUNCATE TABLE there is no warning displayed but the MERGE TABLE…
Post: Extending Index for Innodb tables can hurt performance in a surprising way
May 22, 2010 By 9 Comments
… sec) The obvious optimization is to extend index from column (a) to column (a,b) right which will make it faster and should not hurt any other queries a lot, right ? mysql> alter table idxitest…. These results mean you should be very careful applying index changes from mk-duplicate-key-checker key checker when it comes…
Post: Converting Character Sets
March 17, 2009 By 16 Comments
… ALTER statement against the table in Approach #1: ALTER TABLE `t1` DEFAULT CHARSET=utf8, MODIFY COLUMN `c1` text CHARACTER SET utf8; This approach will both change the default character set for the table…
Post: ANALYZE: MyISAM vs Innodb
September 3, 2008 By 9 Comments
… the table) It is worth to note if you do ALTER TABLE Innodb, same as MyISAM will internally run analyze as soon as table is rebuilt and values will be more sensible: mysql> alter table… see the difference let me set column “c” to NULL in both tables and see how values change: mysql> update antest set c…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…; Query OK, 0 rows affected (0.00 sec) mysql> ALTER TABLE t ADD COLUMN v VARCHAR(1); Query OK, 4194304 rows affected (1… in ALTER TABLE are ignored to enforce uniqueness where necessary when copying the data to a temporary table; ALTER TABLE and OPTIMIZE TABLE always process tables containing… because InnoDB requires a full table rebuild on foreign key changes. So adding them back with a separate ALTER TABLE after restoring the data…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…alter_db_upgradeblogpercona.commanual Com_alter_eventblogpercona.commanual Com_alter_functionblogpercona.commanual Com_alter_procedureblogpercona.commanual Com_alter_serverblogpercona.commanual Com_alter_tableblogpercona.commanual Com_alter…change_dbblogpercona.commanual Com_change…column…
