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Transaction Management

ACID Property in DBMS
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Atomicity: Either all operation of a transaction occurs or none. That means transactions will be atomic.

  • Maintained by Transaction Management Component.

Consistency: Consistency stands for correctness.  This property ensures that any transaction will bring the database from one valid state to another.

  • Responsibility of Application Programmer.

Isolation: Ensures that concurrent execution results in a system state that would be obtained if transaction would be executed serially.

  • Managed by Concurrency Control Manager.

Durability: Changes should be parmanent. The changes must NOT be lost due to some database failure.

  • Responsibility of Recovery Manager.
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Various states of transaction
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A transaction in a database can be in one of the following states:
1. ACTIVE: A transaction goes into an active state immediately after it starts execution, where it can issue READ and WRITE operation.
2. PARTIALLY COMMITTED: When the transaction ends, it moves to the partially committed state. At this point, some recovery protocol need to ensure that a system failure will not result in an inability to record the changes of the transaction permanently.
3. COMMITTED: If the check in the partially committed state is successful, the transaction is said to have reached its commit point and enters in the committed state. Once a transaction is committed, it has concluded its execution successfully and all its changes must be recorded permanently in the database.
4. FAILED: A transaction can go to the failed state, if one of the check fails or if the transaction is aborted during its active state. The transaction may then have to be rolled back to undo the effect of its WRITE operations on the database.
5. TERMINATED: The terminated state corresponds to the transaction leaving the system.

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Problems with Concurrent Execution of Transactions
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Why we need concurrent execution and what are the problems of concurrent execution.

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Transaction Failure, Revovery and Log
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What are the various reasons of transaction failure and the significance of log files in recovery.

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Understanding Schedule and Conflict in Transaction Management
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What is schedule, what are the conflicting operations

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Number of Possible Schedules of given Transaction
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Basics os schedule, Number of possible schedule and Number of possible serial schedule.

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Recoverable and Nonrecoverable Schedules in Transaction
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Understanding the difference between Recoverable and Nonrecoverable Schedules

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Understanding Result Equivalent
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When two schedules are called result equivalent

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Basics of Conflict Equivalence
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When a pair of schedule is Conflict Equivalent

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Understanding Serializability
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What is serializability ? How it effects the performance?

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What is Conflict Serializability ?
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Understanding conflicting operations and Conflict Serializability

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Constructing Precedence Graph to Check Conflict Serializability
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Step by step guideline to construct precedence graph to check whether a view is conflict serialzable. 

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Check if the following schedule is conflict serializable ?

S: R2(z) R2(y) W2(y) R3(y) R3(z) R1(x) W1(x) W3(y) W3(z)

Understanding View Serializability
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What is view serializability and view equivalence

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Why view seriazability ?
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Why there is a need of View Serializability.

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Isolation Levels in Database Management Systems
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The various isolation levels and the terms associated with it.

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Introduction to Concurrency Control Protocol
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What do we mean by Concurrency Control in DBMS? Why is it important?

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Simple Locking Protocol
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How simple locking protocol works

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Problems with simple locking protocol
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Explains why can't simple locking protocol avoid problems related to concurrency.

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Simple 2 - Phase Locking Protocol
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Understanding basic/simple 2-phase locking protocol

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Problems with Basic 2- Phase Locking Protocol
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Understanding why simple 2-phase locking is not the ultimate solution.

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Conservative 2-Phase Locking Protocol
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Understanding Conservative 2-Phase Locking Protocol. How can it avoid deadlock.

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Strict 2-Phase Locking Protocol and Rigorous 2-Phase Locking Protocol
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understanding the basics and difference of Strict 2-Phase Locking Protocol and Rigorous 2-Phase Locking Protocol 

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Understanding Graph-Based Protocol
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What is database graph? How locking and unlocking is done in database graph?

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Checking whether the given schedule follow graph-based protocol

Multiple Granularity Protocol (Part-1)
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What is granularity? How dividing data in multiple level can help achiving concurrency ?

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Multiple Granularity Protocol (Part-2)
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Intension mode locks and compatibility.

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Example to understand Multiple Granularity Protocol.

Understanding Basics of Timestamp Protocol | Concurrency Control
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Basics of Timestamp and Timestamp-Ordering Protocol

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Basic Timestamp Ordering Protocol | Concurrency Control
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What is Basic Timestamp Ordering Protocol? How it helps to achieve concurrency?

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Thomas Write Rule | Concurrency Control
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How Thomas Write Rule is different from Basic Timestamp Ordering.

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Verify if the given schedules are conflict equivalent:

S1: w1(x) r2(z) w2(z) r2(x) r1(y)
S2: w1(x) r2(x) w2(z) w2(y) r1(z)

  • This quiz contains 5 questions on the topic Transaction Management
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Difficulty Level:  intermediate