The document discusses different types of replication in Oracle and SQL Server. It defines replication concepts and covers snapshot replication, transactional replication, merge replication, and peer-to-peer replication. Snapshot replication provides a snapshot of the data at a specific point in time. Transactional replication only allows the publisher to modify data while changes are transmitted in real-time or at intervals. Merge replication allows each server to modify data and changes are synchronized periodically. Peer-to-peer replication allows any node to make changes and modifications are transmitted to all nodes in the topology.

1. Despre replicare
Elena Banea
22.04.2013

2. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

3. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

4. Definire concept
In Oracle, conceptele sunt diferite:
– Articolele = replication objects
– Publisherul = Master database / Materialized View
database
– Subscriberul = Master database / Materialized View
database
SQL Server Replication
Articles
Publisher
Distributor Subscribers

5. Definire concept
Atat in Oracle cat si in SQL Server se pot replica:
– Intregul set de date:

6. Definire concept
Atat in Oracle cat si in SQL Server se pot replica:
– Un subset de date:

7. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

8. Snapshot replication
O imagine a datelor la un anumit moment
Snapshot Writable Materialized View
Modificarile care persista
sunt facute de
Publisher Master
Modificarile facute de
Subcriberi/Materialized view
databases
Se pierd la urmatorul refresh Se pierd la urmatorul refresh
Modificarile ulterioare sunt
transmise
Nu sunt transmise Nu sunt transmise
Poate genera conflicte Nu Nu

9. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

10. Transactional replication
- Doar Publisherul poate modifica datele
- Modificarile pot fi transmise in timp real sau la
un anumit interval
Publisher &
Distributor
(Server1)
Subscriber
(Server3)
Subscriber
(Server2)
Transactional Replication

11. Transactional replication
- Ar putea fi asociat cu Read-Only Materialized
Views din Oracle
Client
application
Master
database
Materialized
view
database
Read-Only Materialized Views
Replicate table data
Remote updateLocal query

12. Transactional replication
Transactional Read-Only Materialized View
Modificarile care persista
sunt facute de
Publisher Master
Modificarile ulterioare
sunt transmise
De la Publisher catre
Subscriberi
De la Master catre Materialized
View databases
Poate genera conflicte Nu Nu
Transactional with
updatable subscriptions
Updatable materialized views
Modificarile care persista
sunt facute de
Publisher & Subscriberi Master & Materialized View
databases
Modificarile ulterioare
sunt transmise
De la Publisher catre
Subscriberi si invers
De la Master catre Materialized
View databases si invers
Poate genera conflicte Da Da

13. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

14. Merge replication
Fiecare server implicat poate modifica datele iar
la un anumit moment se face o sincronizare.
Transactional Merge Transactional with
updatable subscriptions
Modificarile care
persista sunt
facute de
Publisher Publisher &
Subscriberi
Publisher & Subscriberi
Modificarile
ulterioare sunt
transmise
De la Publisher la
Subscriberi
De la Publisher la
Subscriberi si invers
De la Publisher la
Subscriberi si invers
Poate genera
conflicte
Nu Da Da
Aplicatia necesita
acces la starile
intermediare
Da (e.g. daca un rand
se modifica de 5 ori se
va transmite catre
Subscriberi de 5 ori)
Nu (e.g. daca un
rand se modifica de
5 ori se va transmite
catre Subscriberi
doar ultima valoare)
Da (e.g. daca un rand se
modifica de 5 ori se va
transmite catre
Subscriberi de 5 ori)

15. Cuprins
• Definire concept
• Tipuri de replicare
– Snapshot
– Transactional
– Merge
– Peer-to-Peer

16. Peer-to-Peer replication
- Specific pentru Enterprise Edition
- Fiecare nod implicat poate face modificari
Node B
(Server2)
Node A
(Server1)
Peer-to-Peer Replication
Node C
(Server3)
Node B
(Server2)
Peer-to-Peer Replication
Node A
(Server1)

17. Peer-to-Peer replication
• Poate fi asociat cu Multimaster Replication din
Oracle
Master Site
(Server3)
Master Site
(Server2)
Multimaster Replication
Master Site
(Server1)

18. Peer-to-Peer replication
Peer-to-Peer Multimaster
Modificarile care persista
sunt facute de
Any node Any master
Modificarile ulterioare sunt
transmise
Sunt transmise catre toate
nodurile implicate in
topologie
Sunt transmise catre toate
nodurile implicate in
topologie
Poate genera conflicte Da Da
Ofera posibilitatea replicarii
unui subset de date
Nu Nu
Aplicatia necesita acces la
starile intermediare
Da (e.g. daca un rand se
modifica de 5 ori se va
transmite catre Subscriberi
de 5 ori)
Da (e.g. daca un rand se
modifica de 5 ori se va
transmite catre Subscriberi
de 5 ori)

19. Thank You for your time!