A Database already has up to 25-30 tables and all are MyISAM. Most of these tables are related to each other meaning a lot of queries use joins on IDs and retrieve data.
One of the tables contain 7-10 Million records and it becomes slow if i want to perform a search or update or even retrieval of all data. Now i proposed a solution to my boss saying that converting tables into InnoDB might give better performance.
I also explained the benefits of InnoDB:
Since we anyways join multiple tables on keys and they are related, it will be better to use foreign keys and have relational database which will avoid Orphan Rows. I found around 10-15k orphan rows in one of the big tables and had to manually remove them.
Support for transactions, we perform big updates from time to time and if one of them fails on the way we have to replace the entire table with the backed-up one and run the update again to make sure that all queries were executed. With InnoDB we can revert back any changes from query 1 if query 2 fails.
Now the response i got from my boss is that I need to prove that InnoDB will run faster than MyISAM. My question is, wont above 2 things improve the speed of the application itself by eliminating orphan rows?
In general is MyISAM faster than InnoDB?
Note: using MySQL 5.5
You should also mention to your boss probably the biggest benefit you get from InnoDB for large tables with both read/write load - You get row-level locking rather than table-level locking. This can be a great performance benefit for the application in cases where you see a lot of waits for table locks to be released.
Of course the best way to convince your boss is to prove it. Make copies of your large table and place on a testing database. Make one version of data in MyISAM and one in InnoDB. Then run load testing against it with a load mix that approximates your current DB read/write activity. Find out for yourself if it is better.
Just updated for your comment that you are on 5.5. With 5.5 it is a no brainer to use InnoDB. MyISAM engine basically has seen no improvement over the last several years and development effort has been around InnoDB. InnoDB is THE MySQL engine of choice going forward.