Re: InnoDB to MyISAM Disadvantages?

[Rick James]

--- InnoDB -> MyISAM, from the point of view of a customer of a hosted service:

* Lose:
FOREIGN KEYS -- correct code does not need them.
Cascade -- The clauses will be silently ignored. You would need to add code to simulate.
"Transactions" -- BEGIN/COMMIT/ROLLBACK become no-ops; you have to rethink the logic to simulate such. Simply replacing with LOCK TABLE is a start, but not really a substitute.

* Gain:
FULLTEXT indexes.
Some other 'features'.

* It depends:
PRIMARY KEY exists for MyISAM, but it is not "clustered"; this is better or worse depending on details.
Performance -- May or may not improve.

--- From the point of view of the hoster:
* Lose:
Robust restart -- They need to CHECK MyISAM tables for corrupted indexes after a crash.

* Gain:
MyISAM tends to have 2x smaller footprint. (This is the only significant 'resource' difference I can think of.)
Seems like there is some other reason for Hosters to avoid InnoDB.

--- Comments
It is good that they are moving off 4.1; its was End-of-Live some time ago.
It is unfortunate that they are not moving to 5.1.
I would hope they give their customers some guidelines on what to do with their code, especially relating to cascading and transactions. Suggest you raise a stink about this. Otherwise they will make the conversion, then have some percentage of customers with broken database application.

Suggest that they add comments to this Forum thread.