Question

I have a GWT/Java/Hibernate/MySQL application (but I think any web pattern could be valid) that do a CRUD on several objects. Each object is stored in a table in the database. I want to implement an action logger. For example for Object A I want to know who created it and modified it, and for User B, what actions did he perform.

My idea is to have a History table that stores : UserId, ObjectId, ActionName. The UserId and ObjectId are foreign keys. Am I on the right track ?

Answer 1

I also think this is the right direction.
However, bare in mind that in an application with lots of traffic, this logs can become overhead.
I would suggest the following in this case –
A. Don’t use hibernate for this “action logging” – Hibernate has better performance for “mostly read DB”
B. Consider DB that is better in “mostly write” scenario for the action logging table.
You can try to look for a NoSQL solution for this.
C. If you use such NoSQL DB, but still want to keep the logging actions in the relational DB, have an offline process that runs once in a day for example), that will query your “action logging DB” and will insert it to the relational DB.
D. If it’s ok that your system might lose some action logging, consider using producer/consumer pattern (for example – use a queue between producer and consumer thread) – the threads that need to log actions will not log them synchronously, but will log them asynchronously.
E. In addition, don’t forget that such logging table has the potential to be over-flooded in time, causing queries on it to take a long time.
For these issues consider the following:
E.1. Every day remove really old logs – let’s say – older than month, or move them to some “backup” table.
E.2 Index some fields that you mostly use for action logging queries (for example – maybe an action_type) field.