MySQL 5.7使用pt-online-schema-change对大表加字段

来源：这里教程网时间：2026-03-01 12:43:22 作者：

业务需求：对一张线上的3000W行的表加字段：用普通方式，建议小表使用：ALTER TABLE `idempotent`ADD COLUMN `orderid` VARCHAR(20) NULL DEFAULT NULL COMMENT '业务单据号' AFTER `isdelete`; ALTER TABLE ship_type ADD printer_name VARCHAR(50) COMMENT '打印机名称';大表会锁表。对大表加字段，建议用pt-online-schema-change工具，可以不锁表。对表 idempotent加字段 orderid：命令： [root@DB001 ~]#pt-online-schema-change --user=root --password=123456 --host=192.168.1.18 --alter "ADD COLUMN orderid VARCHAR(20) NULL DEFAULT NULL COMMENT '业务单据号'" D=ora,t=idempotent --no-check-replication-filters --execute Found 1 slaves:localhost.localdomain -> 192.168.1.19:socketWill check slave lag on:localhost.localdomain -> 192.168.1.19:socketOperation, tries, wait: analyze_table, 10, 1 copy_rows, 10, 0.25 create_triggers, 10, 1 drop_triggers, 10, 1 swap_tables, 10, 1 update_foreign_keys, 10, 1Altering `ora`.`idempotent`...Creating new table...Created new table ora._idempotent_new OK.Altering new table...Altered `ora`.`_idempotent_new` OK.2019-10-23T19:01:00 Creating triggers...2019-10-23T19:01:00 Created triggers OK.2019-10-23T19:01:00 Copying approximately 24968401 rows...Copying `ora`.`idempotent`: 4% 10:53 remainCopying `ora`.`idempotent`: 8% 10:40 remainCopying `ora`.`idempotent`: 11% 11:49 remainCopying `ora`.`idempotent`: 14% 12:08 remainCopying `ora`.`idempotent`: 17% 12:09 remainCopying `ora`.`idempotent`: 19% 12:15 remainCopying `ora`.`idempotent`: 22% 12:15 remainCopying `ora`.`idempotent`: 24% 12:11 remainCopying `ora`.`idempotent`: 27% 12:09 remainCopying `ora`.`idempotent`: 29% 12:03 remainCopying `ora`.`idempotent`: 31% 11:45 remainCopying `ora`.`idempotent`: 34% 11:23 remainCopying `ora`.`idempotent`: 37% 11:01 remainCopying `ora`.`idempotent`: 39% 10:39 remainCopying `ora`.`idempotent`: 42% 10:11 remainCopying `ora`.`idempotent`: 44% 09:50 remainCopying `ora`.`idempotent`: 47% 09:35 remainCopying `ora`.`idempotent`: 49% 09:14 remainCopying `ora`.`idempotent`: 52% 08:44 remainCopying `ora`.`idempotent`: 55% 08:10 remainCopying `ora`.`idempotent`: 59% 07:17 remainCopying `ora`.`idempotent`: 63% 06:21 remainCopying `ora`.`idempotent`: 67% 05:32 remainCopying `ora`.`idempotent`: 71% 04:44 remainCopying `ora`.`idempotent`: 75% 03:59 remainCopying `ora`.`idempotent`: 80% 03:11 remainCopying `ora`.`idempotent`: 84% 02:28 remainCopying `ora`.`idempotent`: 88% 01:49 remainCopying `ora`.`idempotent`: 92% 01:08 remainCopying `ora`.`idempotent`: 96% 00:28 remain2019-10-23T19:18:24 Copied rows OK.2019-10-23T19:18:24 Analyzing new table...2019-10-23T19:18:24 Swapping tables...2019-10-23T19:18:24 Swapped original and new tables OK.2019-10-23T19:18:24 Dropping old table...2019-10-23T19:18:26 Dropped old table `ora`.`_idempotent_old` OK.2019-10-23T19:18:26 Dropping triggers...2019-10-23T19:18:26 Dropped triggers OK.Successfully altered `ora`.`idempotent`.You have mail in /var/spool/mail/root 整个过程持续10几分钟，不锁表。字段添加完成。 PS：切记在业务低峰运行。

pt-online-schema-change --user=user --password=xxx --host=ip --port=3306 --alter “add column col1 VARCHAR(64) NULL COMMENT ‘订单号’” D=sy,t=t1 --execute --charset=utf8  --nocheck-replication-filters --max-load=“Threads_running=20”可以指定字符集，防止加好字段的表的注释出现乱码。修改注释：ALTER TABLE idempotent MODIFY COLUMN `sysno` BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '编号';