Group 8 part 1

To ensure atomicity despite failures, we first output information describing the modifications to stable storage without modifying the database itself.

is a sequence of log records, which maintains information about update activities on the database. Each entry in the log is referred to as a log record.

identifies different transactions in the log and helps in tracking their progress and status during recovery

identifies the location of the data-item within the database and facilitates the identification of affected data during recovery.

stores the original value of a data item before it was modified by a transaction.

contains the new value that was assigned to a data item by a transaction.

is a technique to ensure database consistency after a system failure. It involves maintaining a transaction log, which records all operations performed by transactions before they are committed to the database and be used as a recovery mechanism.

Analyzes the transaction log to determine the last checkpoint and identify transactions that were active but not yet committed at the time of failure.

Reapplies committed transactions from the log to ensure that all changes are reflected in the database.

Rolls back incomplete transactions that were active but not committed at the time of failure to maintain atomicity.

recovery failure that occurs due to hardware malfunctions, disasters like fires or floods, or human errors like accidental deletion or corruption

When the backup site takes over processing

all transactions share a single disk buffer and a single log

can have data items updated by one or more transactions

are essential components of DBMS that ensure the database can be restored to a consistent state after a failure or crash.

are essential components of DBMS that ensure the database can be restored to a consistent state after a failure or crash.

is the process of recording important events and changes in a database system to a transaction log file.

is the process of undoing the effects of incomplete or aborted transactions to restore the database to a consistent state.

replay updates of all transactions, whether they committed, aborted, or are incomplete

undo all incomplete transactions