CREATE DATABASE IF NOT EXISTS test; USE test; DROP TABLE IF EXISTS test; CREATE TABLE test ( id INT NOT NULL AUTO_INCREMENT,	amount FLOAT(10,4) NOT NULL, PRIMARY KEY(id)) ENGINE=InnoDB; 

vagrant@wheezy:~$ pt-online-schema-change u=root,p=dbpass,D=test,t=test --no-drop-old-table --alter "CHANGE amount amount decimal(15,4) NOT NULL" --execute No slaves found. See --recursion-method if host wheezy has slaves. Not checking slave lag because no slaves were found and --check-slave-lag was not specified. Operation, 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, 1 Altering `test`.`test`... Creating new table... Created new table test._test_new OK. Altering new table... Altered `test`.`_test_new` OK. 2017-01-07T13:52:21 Creating triggers... 2017-01-07T13:52:21 Created triggers OK. 2017-01-07T13:52:21 Copying approximately 10000811 rows... Copying rows caused a MySQL error 1265: Data truncated for column 'amount' at row 1 No more warnings about this MySQL error will be reported. If --statistics was specified, mysql_warning_1265 will list the total count of this MySQL error. Copying `test`.`test`: 27% 01:17 remain Copying `test`.`test`: 55% 00:48 remain Copying `test`.`test`: 79% 00:22 remain 2017-01-07T13:54:14 Copied rows OK. 2017-01-07T13:54:14 Swapping tables... 2017-01-07T13:54:14 Swapped original and new tables OK. Not dropping old table because --no-drop-old-table was specified. 2017-01-07T13:54:14 Dropping triggers... 2017-01-07T13:54:14 Dropped triggers OK. Successfully altered `test`.`test`. vagrant@wheezy:~$