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Database Recovery Using a Transaction Log File

IP.com Disclosure Number: IPCOM000040084D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Caraballo, JF: AUTHOR [+5]

Abstract

This article describes recovering a critical database automatically with a transaction log after the master has been destroyed. The automatic parts inventory (API) system consists of several personal computers in a network environment that has a master computer database and slaves attached. The master computer database is retained in the random-access memory (RAM) and a backup version on a disk media. As transactions are being received at the master station, it broadcasts the transaction to the slave station to keep the databases at all stations identical. Refer to Fig. 1 which shows this configuration. It illustrates that the current master is the input crane. If this station becomes disabled, any of the other stations then can become the master station by changing the station table.

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Database Recovery Using a Transaction Log File

This article describes recovering a critical database automatically with a transaction log after the master has been destroyed. The automatic parts inventory (API) system consists of several personal computers in a network environment that has a master computer database and slaves attached. The master computer database is retained in the random-access memory (RAM) and a backup version on a disk media. As transactions are being received at the master station, it broadcasts the transaction to the slave station to keep the databases at all stations identical. Refer to Fig. 1 which shows this configuration. It illustrates that the current master is the input crane. If this station becomes disabled, any of the other stations then can become the master station by changing the station table. Software is designed in the API system to produce a transaction log as a database is being updated. The API system maintains a current database in the RAM of the master computer and a backup database on the disk media. As transactions are being processed on the database a transaction log is kept of each transaction. After twenty transactions

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have been processed, a program which is at a slave station will do an integrity test, matching the twenty transactions on the log file to the database. If the twenty transactions are verified on the database, the transaction log is then emptied of the transactions, and the current da...