Concurrency control techniques in dbms pdf

1. What is concurrency control techniques in DBMS?
2. What is concurrency control in DBMS PDF?
3. What is the purpose of concurrency control?
4. What is multiple granularity explain with suitable examples?
5. What are the various concurrency control techniques compare lock based concurrency control strategies in detail?
6. How is concurrency control implemented in a distributed database?
7. What are the different concurrency control problems explain with examples?
8. What is the major factor for concurrency control?
9. What is Multiversion schemes in DBMS?
10. What do you mean by multi granularity how the concurrency is maintained in this case?
11. What is lock granularity in DBMS?
12. How many types of concurrency control are there?
13. What is shared lock in DBMS?
14. What is shared and exclusive locks?

What is concurrency control techniques in DBMS?

Concurrency Control in Database Management System is a procedure of managing simultaneous operations without conflicting with each other. It ensures that Database transactions are performed concurrently and accurately to produce correct results without violating data integrity of the respective Database.

What is concurrency control in DBMS PDF?

The concurrency control methods are broadly classified as locking based methods, timestamp ordering based methods and optimistic methods. Two-phase locking based methods are the most popular and widely used methods used in both centralized and distribute framework of the database systems.

What is the purpose of concurrency control?

The goal of concurrency control is to coordinate execution so that the VIEW or effect from the database's perspective is the same as if the concurrently executing transactions were executed in a serial fashion. This scheme is referred to as the serializable execution of transactions.

What is multiple granularity explain with suitable examples?

Now Multiple Granularity means hierarchically breaking up the database into blocks that can be locked and can be tracked needs what needs to lock and in what fashion. Such a hierarchy can be represented graphically as a tree. For example, consider the tree, which consists of four levels of nodes.

What are the various concurrency control techniques compare lock based concurrency control strategies in detail?

What are the various concurrency control techniques? Compare Lock Based concurrency control strategies in detail. Binary Locks − A lock on a data item can be in two states; it is either locked or unlocked. Shared/exclusive − This type of locking mechanism differentiates the locks based on their uses.

How is concurrency control implemented in a distributed database?

Concurrency control in distributed system is achieved by a program which is called scheduler. Scheduler help to order the operations of transaction in such a way that the resulting logs is serializable. There have two type of the concurrency control that are locking approach and non-locking approach.

What are the different concurrency control problems explain with examples?

Concurrency problems occur when multiple transactions execute concurrently in an uncontrolled manner. Dirty Read Problem, Unrepeatable Read Problem, Lost Update Problem, Phantom read Problem are the concurrency problems in DBMS.

What is the major factor for concurrency control?

Providing isolation is the main goal of concurrency control. Durability - Effects of successful (committed) transactions must persist through crashes (typically by recording the transaction's effects and its commit event in a non-volatile memory).

What is Multiversion schemes in DBMS?

A concurrency control scheme using multiple versions of data objects is presented which allows increased concurrency. The scheme grants an appropriate version to each read request. Transactions issuing write requests which might destroy database integrity are aborted.

What do you mean by multi granularity how the concurrency is maintained in this case?

The Multiple Granularity protocol enhances concurrency and reduces lock overhead. ... It maintains the track of what to lock and how to lock. It makes easy to decide either to lock a data item or to unlock a data item. This type of hierarchy can be graphically represented as a tree.

What is lock granularity in DBMS?

The granularity of locks in a database refers to how much of the data is locked at one time. ... Such extremes affect the concurrency (number of users that can access the data) and locking overhead (amount of work to process lock requests) in the server. Adaptive Server supports locking at the table, page, and row level.

How many types of concurrency control are there?

Timestamp Ordering :

Following are the three basic variants of timestamp-based methods of concurrency control: Total timestamp ordering. Partial timestamp ordering. Multiversion timestamp ordering.

What is shared lock in DBMS?

1. Shared lock: It is also known as a Read-only lock. In a shared lock, the data item can only read by the transaction. It can be shared between the transactions because when the transaction holds a lock, then it can't update the data on the data item.

What is shared and exclusive locks?

The two types are exclusive and shared locks. Exclusive locks can be active or retained; shared locks can only be active (see Active and retained states for locks ). Note that there are no delete locks in RLS mode.