PPT-1/11/2012 1 3. Concurrency Control

for Transactions Part One CSEP 545 Transaction Processing Philip A Bernstein Copyright 2012 Philip A Bernstein 1112012 2 Outline 1 A Simple System Model 2 Serializability Theory 3 Synchronization Requirements . This motivated an ongoing shared effort by the standards committees to specify concurrent behaviour in the next versions of both languages They aim to provide strong guarantees for racefree programs together with new but subtle relaxedmemory atomic Slide . 1. Too Much Milk. . Roommate . A. 3:00. Arrive home: no milk. 3:05. Leave for store. 3:10. Arrive at store. 3:15. Leave store. 3:20. Arrive home, put milk away. CS 140 Lecture Notes: Concurrency. 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. What is it?. What is concurrency?. Concurrency is not a new idea…. Concurrency was first developed by the ancient Babylonians.. They thought about stuff, walked, and chewed gum … all at the same time.. 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. Prof. O. Nierstrasz. Selected material © Magee and Kramer. © Oscar Nierstrasz. 2. Roadmap. Modelling Concurrency. Finite State Processes . Labelled Transition Systems. Java Threads. Thread creation. Median of a Triangle. A line segment connecting a vertex of a triangle to the midpoint of the opposite side. On a piece of graph paper, graph the triangle with vertices A(2, 1) B(5, 8) C(8, 3). . Find the midpoint of each side and label the midpoint opposite A “D”, opposite B “E”, opposite C “F”. . Concurrency Topics. 1. Sequential programming notation. 2. Expressing concurrency with . co. and . process. . 3. States and hardware. 4. Atomic actions. 5. Inter-leavings and histories. 6. The finite progress assumption. Concurrency. Multithreaded Programs. Copyright © Texas Education Agency, 2013. Overview. Why Concurrency?. Threads. Scheduling. Runnable interface. Race Conditions. Locks. Thread Safe. Dead Lock. 2. Motivation, Challenges, Impact on Software Development. CSE 110 – Winter 2016. About These Slides. Due to the nature of this material, this lecture was delivered via the chalkboard. Every was advised that slides would not be available and that notes should be taken. . 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. -. Bhavya. . Kilari. Dr. . Yanqing. Zhang, . CSc. 8320. PREVIEW. P. ART. I. : . I. NTRODUCTION. Transaction Processing System [. R. Chow & T. Johnson, 1997. 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 :.