WFS service in Mapserver directly changes the PostgreSQL table whenever performing a transaction operation such as insert, update or delete.
I want a solution which gives me control over what happens when a transaction request is received from the client.
For example, when a new value is inserted, instead of making changes in original table I want to create another table in SQL which would be a clone of previous one and make changes in that table. So, that the original table remains the same.
Looks like a job for a database trigger. Since you mention PostgreSQL, here is some documentation about the topic: https://www.postgresql.org/docs/current/sql-createtrigger.html
Usually you'd handle this with updateable Views as middlelayer; I outlined the general concept in this answer, using INSTEAD OF triggers, and you'll find more info on DBA.SE.
In your case you'd likely want to use support tables much like ESRI's delta table versioning, where any data modification is logged as a sequence of INSERT (A table) and DELETE (D table) operations, including their respectively modified values, and have the View pull live data from a composition of the base table and the A & D tables.
