[MySQL]表在线重定义-pt-online-schema-change_MySQL

wget percona.com/get/percona-toolkit.tar.gztar -zxvf percona-toolkit-2.2.6.tar.gz

--dry-runCreate and alter the new table, but do not create triggers, copy data, or replace the original table.--executeIndicate that you have read the documentation and want to alter the table. You must specify this option to alter the table. If you do not, then the tool will only perform some safety checks and exit. This helps ensure that you have read the documentation and understand how to use this tool. If you have not read the documentation, then do not specify this option.

pt-online-schema-change --alter "modify treatment_afterday INT(4) NULL" D=portal,t=comment_expert -uroot -p*** --dry-runOperation, tries, wait:  copy_rows, 10, 0.25  create_triggers, 10, 1  drop_triggers, 10, 1  swap_tables, 10, 1  update_foreign_keys, 10, 1Starting a dry run.  `portal`.`comment_expert` will not be altered.  Specify --execute instead of --dry-run to alter the table.Creating new table...Created new table portal._comment_expert_new OK.Altering new table...Altered `portal`.`_comment_expert_new` OK.Not creating triggers because this is a dry run.Not copying rows because this is a dry run.Not swapping tables because this is a dry run.Not dropping old table because this is a dry run.Not dropping triggers because this is a dry run.2014-01-14T13:59:08 Dropping new table...2014-01-14T13:59:08 Dropped new table OK.

pt-online-schema-change --alter "modify treatment_afterday INT(4) NULL" D=portal,t=comment_expert -uroot -pzhujie1986 --executeFound 1 slaves:  lx203Will check slave lag on:  lx203Operation, tries, wait:  copy_rows, 10, 0.25  create_triggers, 10, 1  drop_triggers, 10, 1  swap_tables, 10, 1  update_foreign_keys, 10, 1Altering `portal`.`comment_expert`...Creating new table...Created new table portal._comment_expert_new OK.Altering new table...Altered `portal`.`_comment_expert_new` OK.2014-01-14T13:59:20 Creating triggers...2014-01-14T13:59:20 Created triggers OK.2014-01-14T13:59:20 Copying approximately 1165430 rows...Copying `portal`.`comment_expert`:  19% 02:03 remainCopying `portal`.`comment_expert`:  38% 01:37 remainCopying `portal`.`comment_expert`:  55% 01:12 remainCopying `portal`.`comment_expert`:  73% 00:44 remainCopying `portal`.`comment_expert`:  90% 00:15 remain2014-01-14T14:02:08 Copied rows OK.2014-01-14T14:02:08 Swapping tables...2014-01-14T14:02:08 Swapped original and new tables OK.2014-01-14T14:02:08 Dropping old table...2014-01-14T14:02:10 Dropped old table `portal`.`_comment_expert_old` OK.2014-01-14T14:02:10 Dropping triggers...2014-01-14T14:02:10 Dropped triggers OK.Successfully altered `portal`.`comment_expert`.