Explain the concept of two-phase locking, Database Management System

Assignment Help:

Explain the Concept of Two-phase Locking

It concerns the positions of locking and unlocking operations in each transaction.  In this protocol every transaction issue lock and unlock requests in two phases. 

Growing Phase:  In this phase a transaction might acquire locks but may not release any lock. Here the of locks rises from zero to the maximum for the transaction. 

Shrinking Phase:  In this phase a transaction might release locks but may not obtain any new locks. Here the number of locks reduces from maximum to zero. 

The major concept of this protocol is that, all the locks are first obtained before any of the locks released. No new locks can be granted later than the releasing of any lock.


Related Discussions:- Explain the concept of two-phase locking

What is d command work in the respect of qbe, What is D command work in the...

What is D command work in the respect of QBE? D: It is the command inside QBE to delete tuple(s) from the relation.

Explain transaction manager and their work, Explain Transaction manager and...

Explain Transaction manager and their work? Transaction Manager: Ensure the database remains in a constant (correct) state despite system failure, and in which concurrent trans

gaps in sequence values can happen when-sequences, Gaps in sequence values...

Gaps in sequence values can happen when: -     A rollback happens that is when a statement changes are not accepted. -     When the system crashes -     When a sequence i

Define object-oriented database, Question : Object-Oriented Database (O...

Question : Object-Oriented Database (OODM) is defined as a logical data model that captures the semantics of objects supported in object-oriented programming. An Object-Oriente

An Apriori algorithm, Submission Requirements All answers must be co...

Submission Requirements All answers must be computer generated (including text and diagrams). The hand-in version must include a header page (or with sufficient space)

Mis, explain various steps uses in evaluation and maintenance of MIS.

explain various steps uses in evaluation and maintenance of MIS.

What is the candidate key for a table with columns, For problems 1-4, give ...

For problems 1-4, give all candidate keys for the tables with FDs specified.  Composite candidate keys must be put in parentheses, and candidate keys must be separated with commas

File manager-database management system, File Manager File manager ha...

File Manager File manager handles the allocation of space on disk storage. It starts and maintains the list of structures and indices described in the internal schema that is

Which operations need the participating relations to union, Which operation...

Which operations need the participating relations to be union compatible? A UNION, INTERSECTION and DIFFERENCE operations need the participating relations to be union compatibl

Define- relational algebra, Define- relational algebra. The relational ...

Define- relational algebra. The relational algebra is a procedural query language. It having of a set of operations that take one or two relation as input and make a new relati

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd