This document discusses Global Data Services (GDS), which provides intelligent workload management across database replicas in Oracle 12c. It describes how GDS uses components like GDS pools, regions, global service managers, and catalogs to centrally manage services across replicated databases for high availability, load balancing, and automated failover. The key aspects of configuring and using GDS are also outlined.

2. IntelligentWorkload Management
across Database Replicas
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Ritika Nevatia
Under the supervision of Prasanth Kothuri

3. What do we use?
Manual Load Balancing
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4. Can we do better?
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5. Why GDS?
Availability
Scalability
Performance
Manageability
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6. Key features
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Work Load
Management
Centralized Framework
Work Load
Routing
Region based
Replication lag based
Failover Inter database service failover
Role Based
Global Service
Takes care of role transition via Data Guard
Load Balancing Run-time
Connection

7. How GDS works?
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8. Services
Representation
Grouping
Routing
to optimal instance
to handle unexpected failovers
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9. • Implements the Oracle Database service model
• GDSCTL
• Any combination of
• Oracle Data Guard
• Oracle Golden Gate
• or any other database replication technology
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How GDS works?

10. Caution!
Global Data Services is primarily
intended for applications that
are replication-aware.
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Uses read-only global
services
Uses r/w global services BUT
resolves update conflicts if
same service is offered by
more than one DB
Can tolerate replicated data
(potentially stale) due to
replication lag

11. What is GDS made of?
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GDS Pool
GDS Region
Global Service Manager
GDS Catalog
Oracle Notification Servers

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GDS Pool
- Subset of services in same
administrative domain
- Simplifies service management
- Higher security (different admin
for each pool)
- One DB – One Pool
- DBs in the pool need not provide
same service
- All DBs providing same service
need to be in same pool

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GDS Region
- Subset of services in same network
domain
- Low network latency
- Region: LAN or MAN
- One region – multiple pools
- One pool – multiple regions
- Buddy regions for GSM

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Global Service Manager
GSM analogous to remote listener in Oracle
RAC
- Regional listener for connecting to global
services
- Connect time load balancing
- Manage global services across regions
- Collect performance metrics, measure
network latency
- Create run-time load balancing advisory
- Monitor availability of DB instances/global
service and notify their failure
- Each region should have atleast one GSM
- Recommended: 3 GSM per region

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GDS Catalog
- Repository to store config data
- Catalog must reside in 12c DB or
above
- DB can be in/out of the GDS
configuration
- Maybe co-hosted with RMAN or
Oracle Enterprise Manager Catalogs
- Oracle RAC/Data Guard/Clusterware
should be used to enhance availability
of DB where GDS Catalog resides

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Oracle Notification Servers
- Used to receive run-time load
balancing advisory and high
availability events from GSM
- Co-located with each GSM
- All ONS are interconnected
- Clients subscribe to ONS and
receive FAN notifications

19. The process
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Give me
service!
Client GSM Instances
Most
optimal
instance
Service
Catalog

20. More about services
• Functionality of local service is not changed
• Oracle DB 12c provides local and global service
simultaneously
• If you are locally connected to a particular
database, then you can query data on global
services provided by that database
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21. Use Cases
• Load Balancing for Replicated Databases
• Service Failover for Replicated Databases
• Region Affinity in Oracle GoldenGate Multi-Master
• Load Balancing in Oracle GoldenGate Multi-Master
• Balancing Oracle Active Data Guard and Oracle
GoldenGate Reader Farms
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22. Load Balancing in Replicas
• Load metrics
• Region affinity
• Network latency
• Load balancing goals
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Meriyn Budapest

23. Service failovers in Replicas
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Meriyn Budapest Meriyn Budapest

24. Pre-Configuration
1. Review requirements
2. Install GSM
3. Upgrade GDS
4. Start configuration
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25. Configuration
1. Create GDS user
sys@AISBIT:SQL> create user gds identified by "0Gds2015" default tablespace tools temporary
tablespace temp;
sys@AISBIT:SQL> alter user gds quota 10g on tools;
sys@AISBIT:SQL> grant gsmadmin_role to gds;
2. Create GDS Catalog
GDSCTL>create catalog -database AISBIT -user gds/0Gds2015
3. Grant access to gsmcatuser
sys@AISBIP:SQL> alter user gsmcatuser account unlock;
sys@AISBIP:SQL> ALTER USER gsmcatuser IDENTIFIED BY gsm_2015;
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26. Configuration
4. Create GSM
GDSCTL>add gsm -gsm mgsm -listener 10121 -catalog AISBIT
5. SetTime zone for DB
6. Connect to GDS
GDSCTL>connect gds@itrac50018-v:10121:aisbip1
7. Create Pool
GDSCTL> add gdspool -dbpool hr -users gds
8. Create Region
GDSCTL> add region –region west,east
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27. Configuration
8. Create Databases
GDSCTL>add database -connect ERTS_RAC4 -region REGIONORA -gdspool DBPOOLORA
GDSCTL>add database -connect ERTS_RAC5 -region REGIONORA -gdspool DBPOOLORA
9. Create Service
GDSCTL>add service -gdspool DBPOOLORA -service erts_rw -clbgoal LONG -commit_outcome TRUE
-preferred ERTS_RAC4 -available ERTS_RAC5 -commit_outcome TRUE -notification
TRUE -policy automatic -failoverdelay 10 -failoverretry 6 -session_state DYNAMIC
–failovertype TRANSACTION
10. Start Service
GDSCTL>start service –service erts_rw
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28. Instance Modification
GDSCTL>modify service -service erts_rw -database
erts_rac4 -modify_instances -preferred ERTS -
gdspool erts
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29. Global Services Attributes
Failover
failoverdelay failover_delay
failovermethod {NONE |
BASIC}
failoverretry failover_retries
failovertype {NONE |
SESSION | SELECT |
TRANSACTION}
Preferred or
available
databases
available db_list
preferred dbname_list
preferred_all
Region affinity
locality {ANYWHERE |
LOCAL_ONLY}
lag {lag_value | ANY}
region_failover
Goal and Roles
clbgoal {SHORT | LONG}
rlbgoal {SERVICE_TIME |
THROUGHPUT}
role {[PRIMARY] |
[PHYSICAL_STANDBY] [-
failover_primary]
|[LOGICAL_STANDBY]
|[SNAPSHOT_STANDBY]}
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30. Limitations
Oracle 12C
Limited Documentation
Limited Usage
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ThankYou
Ritika Nevatia
nevatiaritika@gmail.com
@beingritika