PPT-Transaction And Concurrency Control

Bhavya Kilari Dr Yanqing Zhang CSc 8320 PREVIEW P ART I I NTRODUCTION Transaction Processing System R Chow amp T Johnson 1997. Sadhna Kumari. OUTLINE. ACID Properties. 2-Phase Commit Protocol. TPS. Serializability. Concurrency Control Protocols. Current Research. Future. References. ACID PROPERTIES. Atomicity: . A . transaction is . 1. Emmett . Witchel. The University of Texas At Austin. Q: When is everything happening?. A: Now. A: Concurrently. 2. Concurrency is central to CS. CS is at forefront of understanding concurrency. We operate near light speed. Seminar: Transaction Processing (Bachelor). SS 2009. Dennis . Stratmann. Outline. Goal and Overview. Examine Three Approaches to CC on RD:. 1. Predicate-Oriented Concurrency Control. 2. Relational Update Transactions. concurrency. . controll. Chapter. 13. “Distributed Systems: . Concepts and Design”. Coulouris. , . Dollimore. , Kindberg. Hanna. Björling, . Stina Fröjd & Liv Sundman. Transaction. A transaction is a point where there is interaction with the database. -. Bhavya. . Kilari. Dr. . Yanqing. Zhang, . CSc. 8320. PREVIEW. P. ART. I. : . I. NTRODUCTION. Transaction Processing System. [. R. Chow & T. Johnson, 1997. Database System Implementation CSE 507. Some slides adapted from . Navathe. et. Al. , . Silberchatz. et. Al and . Hector Garcia-Molina . Lock Based Protocols. A lock is a mechanism to control concurrent access to a data item. Concurrency Control. Locking. Atomic statement. Can be used to perform two or more updates atomically. Th1: …. < x = x + 1; y = z>;…….. Th2:………….<m = m + 1;….>;…….. Transactions. Database Concurrency Control. 1 Purpose of Concurrency Control. To enforce Isolation (through mutual exclusion) among conflicting transactions. . To preserve database consistency through consistency preserving execution of transactions.. in SDD-1. Philip A. Bernstein. Microsoft Research. SDD-1. A DARPA-funded research project at Computer Corporation of America (Cambridge, MA) to build a distributed database system. Started in the fall of 1976. 1. Emmett . Witchel. The University of Texas At Austin. Q: When is everything happening?. A: Now. A: Concurrently. 2. Concurrency is central to CS. CS is at forefront of understanding concurrency. We operate near light speed. Introduction. Concurrency control protocols. Set of rules to guarantee serializability. Two-phase locking protocols. Lock data items to prevent concurrent access. Timestamp. Unique identifier for each transaction. Sadhna Kumari. OUTLINE. ACID Properties. 2-Phase Commit Protocol. TPS. Serializability. Concurrency Control Protocols. Current Research. Future. References. ACID PROPERTIES. Atomicity: . A . transaction is . Some slides adapted from . Navathe. et. Al. , . Silberchatz. et. Al and . Hector Garcia-Molina . Lock Based Protocols. A lock is a mechanism to control concurrent access to a data item. Data items can be locked in two modes :. Contents. Transaction. . control. Data Concurrency and Consistency in a Multiuser Environment. Locking. A Banking Transaction.               . Transactions - Rationale. Consider two clients booking airline tickets.