ORGANOCHLORINE AND HEAVY METALS RESIDUES IN THE NEARSHORE BIOTA OF THE CANADIAN LOWER GREAT LAKES

The disclosure relates to a transaction processing system where audit information for database updates and the status of transactions in process is sequentially written in audit records in an audit file, where the audit file may be used to restore the database to a consistent state following a system failure. The invention decreases the overhead processing required for auditing, and at the same time minimizes the impact the auditing has on the processing time required for restoring the database. A value which references the location in the audit file at which recovery of the database may begin is conditionally updated each time a page of the database which is cached in the main memory of the data processing system is written to non-volatile storage, based upon the position of the earliest written audit record which is associated with the cached page. In addition, when processing of a transaction is complete, the transaction identifier of the oldest incomplete transaction is saved in the audit record for the completed transaction. When restoring the database to a consistent state, the value which is maintained according to the earliest written audit record and the transaction identifier of the oldest incomplete transaction are used as reference points in the audit file to minimize the processing required to restore the database.