Audit Using Hibernate Envers

Question

I am using hibernate envers for making history of my data, it's working fine as well. The problem here is, it's creating duplicate data in history table ie creating data in history table whether there is any change in audited table or not. I want only changed fields stored in my history table. I am new to hibernate envers. What can I do?

Answer 1

If I understand your question correctly, Envers doesn't work that way, at least not out of the box.

Envers is a commit-snapshot auditing solution where just before commit, it examines audited entity state and determines whether any attributes have been modified or not and records a snapshot of all audited fields of that entity at that point in time. This means that the only time an audit entry isn't created is when no attributes have been modified.

But it also uses the snapshot approach because it fits really well with the Query API.

Consider the inefficiency that would occur if a query to find an entity at a given revision had to read all rows from that revision back to the beginning of time, iterating each row and merging the column state captured to just instantiate a single row result-set.

With the snapshot approach, it boils down to the following query, no loops or iterative work.

SELECT e FROM AuditedEntity e WHERE e.revisionNumber = :revisionNumber

This is far more efficient from a I/O perspective both with the database reading the data pages and the network for streaming a single row result-set rather than multi-row result-set to the client.

I'd say in this case, the saying "space is cheap" really holds true when you compare that against the cost and inefficiencies your application would face doing it any other way.

If this is something you'd like Envers to support, perhaps via some user configured strategy then you're welcomed to log a new feature request in JIRA for hibernate-envers and I can take a look at its feasibility.

Answer 2

I had similar problem.

In my case the error was that audited field had higher precision than the database field. Please see my reply to another thread: https://stackoverflow.com/a/65844949/13381019