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DBMS by Mind Map: DBMS

1. Transaction

1.1. Recovery

1.1.1. Log based Recovery Deferred modification technique Immediate modification technique

1.2. ACID property

1.2.1. Atomicity

1.2.2. Consistency

1.2.3. Isolation

1.2.4. Durability

2. Concurrency Control

2.1. Serializability

2.1.1. Serializable Schedule Conflict Serializable View Serializable

2.1.2. Non-Serializable

2.2. Concurrency Control Techniques

2.2.1. Lock Based Protocol Basic 2-phase locking Protocol 2 Phase Advantages Lock starting of transactions with same variable Strict 2-PL protocol Exclusive Lock Unlock only after Transaction Commit Recoverable Deadlock Possible Rigorous 2-PL Protocol Exclusive/Shared Lock, Unlock tabhi honge jb Transaction Commit ho jae Recoverable Deadlock Possible Conservative 2-PL Protocol Trans. will start only when jb usko sare lock mil jaenge Serializable No Deadlock Lock Upgradation / Downgradation Upgradation Downgradation Advantages

2.2.2. Tree Protocol Advantages ensure Conflict Serializable Deadlock Free Unlock anyTime More Concurrency than 2-Phase Locking Disadvantages Cascading Rollback Can't be Cyclic

2.2.3. Time-Stamp Protocol 2-Data item R-timestamp(X) W-timestamp(X) Issues Ti issue Read(X) Ti issue Write(X) Advantages ensure Serializable Free from Deadlock DiaAdvantage Starvation THOMAS Write Rule Ignore outdated writes