Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Two Phase Locking (2PL)
The two-phase locking protocol having of two phases:
Phase 1: The lock acquisition phase: If a transaction T needs to read an object, it wants to obtain the S (shared) lock. If T needs to modify an object, it wants to obtain X (exclusive) lock. No conflicting locks are granted to a transaction. New locks on items can be obtained but no lock can be released till all the locks needed by the transaction are obtained.
Phase 2: Lock Release Phase: The existing locks can be released in any order but no new lock can be obtained after a lock has been released. The locks are held only till they are needed.
Normally the locks are taken by the DBMS. Any legal schedule of transactions that follows 2 phase locking protocol is sured to be serialisable. The 2 phase locking protocol has been confirmed for it correctness. Though, the proof of this protocol is beyond the scope of this Unit. You can refer to more readings for more details on this protocol.
Step 1 . Using Oracle, create the tables identified in the preferred solution for Assignment 2. Technicians (ZipCode, TechnicianID, FirstName, LastName, Street, City, State, Home
Consider the following relations: BRANCH( bno, street, area, city, pcode, Tel_no, Fax_no) STAFF( Sno, Fname, Lname, address, position , salary, bno) Express the subsequent qu
Explain sorted File with advantages? Sorted file The sort utility shall perform one of the subsequent functions: 1.Sort lines of all the named files together and write the
What is deadlock? Neither of the transaction can ever proceed with its normal implementation. This situation is known as deadlock.
i want notes on this topic
These are the binary operations; i.e., each is applied to two relations or sets. These two relations can be union compatible excluding in case of Cartesian product. Two relations R
how to write tables and drow E-R diagrams for hosiptal management system and how to normalize and cardinalities?
Differentiate strict two phase locking protocol and rigorous two phase locking protocol. In strict two phase locking protocol all exclusive mode locks taken by a transaction is
Consider the following database containing five transactions. Let min_sup = 60%. Mine all frequent itemsets using Apriori and FP-growth algorithm. Compare the efficiency of the t
Write short notes on Schema diagram. A database schema along with primary key and foreign key dependencies can be depicted pictorially by schema diagram. Every relation appea
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd