What is Check Point & log based recovery?

Checkpoint is a mechanism where all the previous logs are removed from the system and stored permanently in a storage disk. Checkpoint declares a point before which the DBMS was in consistent state, and all the transactions were committed.

What are the types of database recovery?

There are three basic types of recovery: instance recovery, crash recovery, and media recovery.

What are database recovery techniques?

The techniques used to recover the lost data due to system crash, transaction errors, viruses, catastrophic failure, incorrect commands execution etc. are database recovery techniques. So to prevent data loss recovery techniques based on deferred update and immediate update or backing up data can be used.

What is SQL checkpoint?

A checkpoint creates a known good point from which the SQL Server Database Engine can start applying changes contained in the log during recovery after an unexpected shutdown or crash.

What is log based recovery in DBMS?

Log-based recovery provides the facility to maintain or recover data if any failure may occur in the system. Log means sequence of records or data, each transaction DBMS creates a log in some stable storage device so that we easily recover data if any failure may occur.

Is SQL DBMS or RDBMS?

Is SQL a DBMS or RDBMS? SQL is neither a DBMS or RDBMS. It is a programming language used to query data on either of the database management systems.

What is checkpoint used for?

Checkpoints are most commonly used to create backups before conducting updates. Should an update fail or cause problems, the administrator can return the virtual machine to its state prior to the update. The recover action is used to return the system to the checkpoint state.

What are the two types of checkpoint?

There are two types of checkpoint: mobile and fixed.

What is log based recovery explain immediate database modification?

Immediate database modification It modifies the database after a write operation, database modification is immediately done when a transaction performs an update/ write operation. Update log records maintain both old and new values of data items. The recovery system uses two operations, which are as follows −

Definition of DBMS Log-Based Recovery Log-based recovery provides the facility to maintain or recover data if any failure may occur in the system. Log means sequence of records or data, each transaction DBMS creates a log in some stable storage device so that we easily recover data if any failure may occur.

What is loglog in DBMS?

Log means sequence of records or data, each transaction DBMS creates a log in some stable storage device so that we easily recover data if any failure may occur. When we perform any operation on the database at that time it will be recorded into a log file.

What is log and log records in SQL Server?

Log and log records – The log is a sequence of log records, recording all the update activities in the database. In a stable storage, logs for each transaction are maintained. Any operation which is performed on the database is recorded is on the log.

How does the recovery subsystem decide which transaction to redone?

After a failure, the recovery subsystem consults the log to determine which transaction need to to be redone. Transaction Ti is redone if and only if the log record contains both and statements.