ΠΡΟΒΛΗΜΑΤΑ ΣΥΝΤΟΝΙΣΜΟΥ ΤΑΥΤΟΧΡΟΝΩΝ ΠΡΟΣΠΕΛΑΣΕΩΝ ΣΕ ΒΑΣΕΙΣ ΔΕΔΟΜΕΝΩΝ

THIS THESIS DEALS WITH SOME ISSUES IN CONCURRENCY CONTROL OF DATABASE ACCESSES. MULTIVERSION SCHEDULERS ARE NOW A WIDELY ACCEPTED METHOD FOR ENHANCING THE PERFORMANCE OF THE CONCURRENCY CONTROL COMPONENT OF A DATABASE. IN THE 2ND CHAPTER OF THE THESIS WE INTRODUCE A NEW NOTION OF MULTIVERSION SERIALIZABILITY (MVSR) BASED ON CONFLICTS (MVCSR) AND DISCUSS ITS RELATION WITH THE WELL KNOWN SINGLE VERSION CONFLICT SERIALIZABILITY (CSR). WE PROVE THAT IT IS NP-COMPLETE TO DECIDE WHETHER A SET OF SCHEDULES IS ON-LINE SCHEDULABLE (OLS). WE INTRODUCE THE CONCEPT OF MAXIMAL OLS SETS AND SHOW THAT NO EFFICIENT SCHEDULER CAN BEDESGNED THAT RECOGNIZES MAXIMAL SUBSETS OF MVSR OR MVCSR. FINALLY A GENERAL FRAMEWORK FOR ALGORITHMS BASED ON MVCSR IS PRESENTED. IN CHAPTER 3 WE SOLVE AN OPEN PROBLEM FOR THE WELL KNOWN CONFLICT GRAPH SCHEDULER: WHEN CAN A NODE BE DELETED FROM THE GRAPH AFTER THE COMPLETION OF THE CORRESPONDING TRANSACTION? WE GIVE A SUFFICIENT AND NECESSARY CONDITION FOR THIS. WE EXAMINE THE DYNAMIC PROBLEM, I.E. REPEATEDLY DELETING NODES AS THE SCHEDULE PROCEEDS AND WE STUDY THE PROBLEM UNDER SEVERAL VARIATIONS OF THE TRANSACTIONS MODEL.

Grantor dc:publisher

University of Patras

Year dc:date

1986

Authors dc:creator

• Hatzilacos, Thanasis
• Χατζηλάκος, Αθανάσιος

• Βάσεις δεδομένων
• ΔΙΑΓΡΑΦΗΔΟΣΟΛΗΨΙΩΝ
• ΘΕΩΡΙΑ ΒΑΣΕΩΝ ΔΕΔΟΜΕΝΩΝ
• ΠΛΗΡΟΤΗΤΑ ΣΤΟ NP
• Πληροφορική
• ΣΕΙΡΙΟΠΟΙΗΣΙΜΟΤΗΤΑ ΑΝΤΙΘΕΣΕΩΝ
• ΣΥΝΤΟΝΙΣΜΟΣ ΜΕ ΑΝΤΙΓΡΑΦΑ
• ΣΥΝΤΟΝΙΣΜΟΣ ΠΡΟΣΠΕΛΑΣΕΩΝ
• Συντονιστές
• ΣΥΝΤΟΝΙΣΤΗΣ ΓΡΑΦΟΥ ΑΝΤΙΘΕΣΕΩΝ
• CONCURRENCY CONTROL
• CONFLICT GRAPH SCHEDULER
• CONFLICT SERIALIZABILITY
• DATABASE SYSTEMS
• DELETING TRANSACTIONS
• MULTIVERSION CONCURRENCY
• NP - completeness
• Schedulers
• Φυσικές Επιστήμες
• Επιστήμη Ηλεκτρονικών Υπολογιστών και Πληροφορική
• Επιστήμες Μηχανικού και Τεχνολογία
• Επιστήμη Ηλεκτρολόγου Μηχανικού, Ηλεκτρονικού Μηχανικού, Μηχανικού Η/Υ
• Natural Sciences
• Computer and Information Sciences
• Engineering and Technology
• Electrical Engineering, Electronic Engineering, Information Engineering

Language dc:language

gre

Identifier

10.12681/eadd/0172

OAI identifier oai:identifier

oai:10442/0172