Cloud CM-IPMP Guide de dépannage Page 194

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 201
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 193
Appendix D
Transactions
D.1 Introduction
This appendix provides a brief overview of transactions and transaction processing systems including the ACID properties of
Transactions, various Concurrency Control Models, components of a transaction processing system and commit protocols.
Transactions are a part of the JAIN SLEE event and programming models, therefore it is important that these concepts are
understood. Rhino provides a sophisticated transaction processing system, and is able to trade durability with performance in a
number of ways.
D.2 ACID Properties
The ACID properties of transactions greatly simplify both the normal runtime logic of an application (in terms of concurrency
control, and updates to state), and the failure-recovery logic of applications. Very briefly these properties are:
Atomicity - A transaction either completes successfully, and the effects of all of its operations are recorded, or it has no
effect at all.
Consistency - A transaction takes the state of the system from one consistent state to another consistent state.
Isolation - Each transaction is performed without interference from other transactions; in other words, the intermediate
effects of a transaction are not visible to other transactions.
Durability - After a transaction has completed successfully, its effects are saved to storage. The storage may be non-
volatile or volatile.
D.3 Concurrency Control Models
There are two general approaches for supporting isolation in a transacted environment. These are pessimistic and optimistic
concurrency control.
This appendix describes the high level approach taken for pessimistic and optimistic concurrency control. It is intended to
provide the developer and administrator knowledge of the general approaches, as the algorithms used to support pessimistic and
optimistic concurrency control vary depending on the underlying Resource Manager (for example different relational databases
may support one and not the other, or may use different variations of algorithms than those described here).
D.3.1 Pessimistic Concurrency Control
Under the pessimistic model the resource manager acquires a lock (shared or exclusive depending on the semantics of the
access) as each addressable unit of transacted state is first accessed. Units of transacted state in JAIN SLEE include SBB
185
Vue de la page 193

Commentaires sur ces manuels

Pas de commentaire

ActiveJet EXPACJAHP0211 podręczniki

Instrukcje obsługi i podręczniki użytkownika dla Wkłady atramentowe ActiveJet EXPACJAHP0211.
Dostarczamy 1 pdf podręczników ActiveJet EXPACJAHP0211 do pobrania za darmo według typów dokumentów: Arkusz Danych


Activejet EXPACJAHP0211 Arkusz Danych (1 strony)


Marka: Activejet | Kategoria: Ink cartridges | Rozmiar: 0.07 MB |

 

Spis treści





Więcej produktów i instrukcji dla Wkłady atramentowe ActiveJet

Modele Rodzaj dokumentu
EXPACJACA0119 Arkusz Danych   ActiveJet AC-526YR, 1 strony
EXPACJACA0115 Arkusz Danych   ActiveJet PGI-525Bk, 1 strony
EXPACJACA0118 Arkusz Danych   ActiveJet AC-526MR, 1 strony
EXPACJAHP0164 Arkusz Danych   ActiveJet AH-920CCX, 1 strony
EXPACJAHP0163 Arkusz Danych   ActiveJet AH-920BC, 1 strony
EXPACJABR0050 Arkusz Danych   ActiveJet AB-M900R, 1 strony
EXPACJABR0052 Arkusz Danych   ActiveJet AB-M1100R, 1 strony
EXPACJACA0104 Arkusz Danych ActiveJet AC-511R, 1 strony
EXPACJACA0092 Arkusz Danych   ActiveJet AC-520BR, 1 strony
EXPACJACA0040 Arkusz Danych   ActiveJet AC-41, 1 strony
EXPACJAEP0250 Arkusz Danych   ActiveJet AE-M715R, 1 strony
EXPACJAHP0038 Arkusz Danych   ActiveJet AH-344R, 1 strony
EXPACJACA0128 Arkusz Danych   ActiveJet AC-M521R, 1 strony
EXPACJAHP0036 Arkusz Danych   ActiveJet AH-339R, 1 strony