Using MyISAM tables?

Jean-nicolas Jolivet wrote:

I was wondering if there were any drawbacks in using MyISAM tables
instead of InnoDB? Main reason is that I have limited memory on my VPS
and skipping innodb tables makes a considerable difference in memory
You may want to try PostgreSQL then... When I started using a 64MB VPS I
tried MySQL hoping it was lightweight compared to the more feature-rich
PostgreSQL, I was disappointed.

I know that rails migration create InnoDB tables by default, I was
wondering if there are any reasons for this or if I can just use MyISAM
without noticing any difference on the coding end... ?
On the coding end, there's no difference, but :
- transactions will not be used without any warning (the SQL will be
executed but no rollback will ever happen in case of failure),
- concurrent access to the DB will be slow (no row-level locking),
should not be a problem on a memory constrained system though,
- you will rely entirely on ActiverRecord validations to enforce foreign
keys (there are race conditions that can corrupt your database instead
of triggering an exception),