PostgreSQL timetravel.c patch

PostgreSQL provides a sample trigger timetravel which can be used to log all changes to a database row. Two columns must be added to any table which should use this feature: start_date and stop_date. Additionaly three more columns can be used to log the login name of the user inserting, updating or deleting a row.

Each time a new row is inserted the start_date is set to the current time and stop_date is set to infinity. If an entry is deleted the stop_date is set to the current time. Each update will modify the existing row setting its stop_date and insert a new row containing the updated row with the correct start_date.

Thus the table will contain the history of each row. The currently active rows can be selected by using a ‘WHERE stop_date = infinity’ clause.

By default timetravel uses the abstime type internally, which is deprecated. The following patch will replace abstime with timestamp with time zone. It is licensed under the BSD license.

Any comments, suggestions or bug reports are welcome.