Mixing MyISAM and InnoDB tables

[sebastfr]

InnoDB became the default engine for MySQL since v5.5 which is installed on recent Ubuntu (and probably others).

Upgrading a repository which had MyISAM tables (the former default) may end up in the repo DB having a mix between MyISAM and InnoDB tables.

EPrints (Database/mysql.pm) should always set a default engine (on create tables) to prevent this situation from happening. Alternatively $c->{dbengine} = 'MyISAM' can be set in the local config.

[sebastfr]

1- need a fix for new eprints users - cf description above
2- need a "fix", instructions or a script for IR's which have mixed tables.

[drn05r]

I have added a page to the wiki to provide a script for converting the database tables:

https://wiki.eprints.org/w/Converting_MyISAM_tables_to_InnoDB

[jesusbagpuss]

@drn05r I think there might be some additional checks that should be made with your script.
This thread is related: http://threader.ecs.soton.ac.uk/lists/eprints_tech/21835.html
where some tables end up without a primary key.
In this situation, as I understand it, InnoDB will create an index in the background for itself, but an application would not then be able to use it.
Defining a PK before altering the table engine it probably a good idea.

It would probably be worth linking to some information about the storage size of InnoDB vs MyISAM too - don't want someone to fill their server up trying to change the DB engine!