Converting a big MyISAM to InnoDB

Question

I'm trying to convert a 10million rows MySQL MyISAM table into InnoDB.
I tried ALTER TABLE but that made my server get stuck so I killed the mysql manually. What is the recommended way to do so?

Options I've thought about:
1. Making a new table which is InnoDB and inserting parts of the data each time.
2. Dumping the table into a text file and then doing LOAD FILE
3. Trying again and just keep the server non-responsive till he finishes (I tried for 2hours and the server is a production server so I prefer to keep it running)
4. Duplicating the table, Removing its indexes, then converting, and then adding indexes

Answer 1

Changing the engine of the table requires rewrite of the table, and that's why the table is not available for so long. Removing indexes, then converting, and adding indexes, may speed up the initial convert, but adding index creates a read lock on your table, so the effect in the end will be the same. Making new table and transferring the data is the way to go. Usually this is done in 2 parts - first copy records, then replay any changes that were done while copying the records. If you can afford disabling inserts/updates in the table, while leaving the reads, this is not a problem. If not, there are several possible solutions. One of them is to use facebook's online schema change tool. Another option is to set the application to write in both tables, while migrating the records, than switch only to the new record. This depends on the application code and crucial part is handling unique keys / duplicates, as in the old table you may update record, while in the new you need to insert it. (here transaction isolation level may also play crucial role, lower it as much as you can). "Classic" way is to use replication, which, as far as I know is also done in 2 parts - you start replication, recording the master position, then import dump of the database in the second server, then start it as a slave to catch up with changes.

Answer 2

Have you tried to order your data first by the PK ? eg:

ALTER TABLE tablename ORDER BY PK_column;

should speed up the conversion.