Hi, I have upgraded/moved recently from MySQL 5.5 To Percona Server 5.6 and for the first time I am going to execute some online DDL’s while the sites are up and the tables that are being modified are pretty big several of them have 10 million records and the largest one has 30 million records.
Given the situation, I would like to know if anyone did online schema changes in their Production environment, if so did you see any issues specifically when the ALTER runs for a very long time accumulating all the changes in a log file with max default maxsize at 128MB (innodb_online_alter_log_max_size).
- Is the default size enough for this log file for ALTER’s involving BIG tables and on a busy site.
- According to the docs adding a column involves copying the table, but it does let me specify the ALGORITHM=INPLACE, LOCK=NONE when adding a new column? does this mean mysql will not do a copy table for adding new columns?
- Did you ever fill out the online ddl log file and had to specify a bigger size at the session level.
Appreciate any feedback.