Product Documentation

FairCom ISAM for C

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Automatic Recovery

Once you establish full transaction processing using the ctTRNLOG file mode, you can take advantage of the automatic recovery feature. Atomicity will generally prevent problems of files being partially updated. However, there are still situations where a system crash can cause data to be lost. Once you have signaled the end of a transaction, there still is a “window of vulnerability” while the application is actually committing the transaction updates to disk. In addition, for speed considerations some systems may buffer the data files and indexes, so that updates may not be flushed to disk immediately. If the system crashes, and one of these problems exist, the recovery logic detects it. If you set up the system for automatic file recovery, the recovery logic automatically resets the database back to the last, most complete, state that it can. If any transaction sets have not been completed, or “committed”, they will not effect on the database.

FairCom offers the most complete set of transaction processing functions and capabilities of any file management product on the market today. By using these functions properly, we can provide both atomicity and automatic recovery.