Term: 2nd Term
Week: 1
Class: Senior Secondary School 3
Age: 17 years
Duration: 40 minutes of 2 periods each
Date:
Subject: Data Processing
Topic:- Crash recovery I
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, pictures, Data Processing for senior Secondary Education by Hiit Plc, WAPB Computer Studies for Senior Secondary I by Adekunle et al, On-line Materials.
INSTRUCTIONAL PROCEDURES
PERIOD 1-2
PRESENTATION |
TEACHER’S ACTIVITY |
STUDENT’S ACTIVITY |
STEP 1 INTRODUCTION |
The teacher reviews the previous lesson on the role of a database administrator |
Students pay attention |
STEP 2 EXPLANATION |
He explains the meaning of crash recovery and states the conditions that could result in transaction failure
|
Students pay attention and participates |
STEP 3 DEMONSTRATION |
He discusses ARIES and the principles behind it. He also outlines the recovery procedures after a crash |
Students pay attention and participate |
STEP 4 NOTE TAKING |
The teacher writes a summarized note on the board |
The students copy the note in their books |
NOTE
CRASH RECOVERY
Crash recovery is the process by which the database is moved back to a consistent and usable state. This is done by rolling back incomplete transactions and completing committed transactions that were still in memory when the crash occurred. When the database is in a consistent and usable state, it has attained what is known as a point of consistency. Following a transaction failure, the database must be recovered.
CONDITIONS THAT CAN RESULT IN TRANSACTION FAILURE INCLUDE:
INTRODUCTION TO ARIES (ALGORITHMS FOR RECOVERY AND ISOLATION EXPLOITING SEMANTICS
ARIES
This is a recovery algorithm designed to work with no-force, steal database approach. It is used by IBM DB2, MS SQL Server and many other database systems.
The three main principles that lie behind ARIES recovery algorithm
RECOVERY PROCEDURE AFTER CRASH
The recovery works in three phases
EVALUATION: 1. Explain the meaning of crash recovery
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively