Oracle Active Data Guard 12cR2. Is it the best option?

Oracle Active Data Guard 12cR2
Is it the best option?
Ludovico Caldara
Oracle ACE Director
Senior Consultant
@ ludodba DOAG2017

About Ludovico Caldara
Oracle Active Data Guard 12cR2. Is it the best option?2 12/2/2017
■ 18 Years DBA (Not Only Oracle)
▪ I do it everywhere (even Windows)
■ RAC ATTACK Ninja & co-writer
■ President, SOUG & ITOUG Board
■ OCP (11g, 12c, MySQL) & OCE
■ Italian living in Switzerland
■ http://www.ludovicocaldara.net
■ @ludodba ludodba
■ ludovicocaldara

Our company.
Trivadis is a market leader in IT consulting, system integration, solution engineering
and the provision of IT services focusing on and
technologies in Switzerland, Germany, Austria and Denmark.
We offer our services in the following strategic business fields:
Trivadis Services takes over the interactive operation of your IT systems.
O P E R A T I O N

COPENHAGEN
MUNICH
LAUSANNE
BERN
ZURICH
BRUGG
GENEVA
HAMBURG
DÜSSELDORF
FRANKFURT
STUTTGART
FREIBURG
BASEL
VIENNA
With over 600 specialists and IT experts in your region.
14 Trivadis branches and more than
600 employees
200 Service Level Agreements
Over 4,000 training participants
Research and development budget:
CHF 5.0 / EUR 4 million
Financially self-supporting and
sustainably profitable
Experience from more than 1,900
projects per year at over 800
customers

My experiences with German
Ich möchte ein Bier, bitte!

My experiences with German
Es ist nicht ein Problem mit der Datenbank

Duolingo level 3!

Duolingo level 3!
Die Suppe ist schlect.

Duolingo level 3!
Die Suppe ist schlect.
Können Sie bitte aufhören, Rapport-Anfragen
auf den Produktionsdatenbanken zu erstellen?
Sie verlangsamen unser Geschäft.

Oracle
Data Guard?

Why is Oracle Data Guard still relevant?
The best high availability solution in the Oracle ecosystem
– Synchronous (or not)
– One-to-one copy (or one-to-many)
– No single points of failure
– Failover is (almost) transparent to the applications (if well configured)
Rock solid!
Included in Oracle Database Enterprise Edition

Active Data Guard?

Agenda… or which features I will try to cover
Real-time Query
Automatic Block Repair
Fast Incremental Backup on Standby
Advanced topologies (Real-time Cascading Standby, Far Sync Standby, Alternate
destinations)
Application Continuity
Rolling Upgrades
Global Data Services
Subset Standby
Multiple Instance Redo Apply

Agenda… or which features I will try to cover
Real-time Query
Fast Incremental Backup on Standby
Advanced topologies (Real-time Cascading Standby, Far Sync Standby, Alternate
destinations)
Rolling Upgrades
Subset Standby
Multiple Instance Redo Apply
We are talking
about extra-cost
features!

Real-time Query
(11g)

Without Real-Time Query
sour_ludo sour_vico
sour_RW
CLIENTS
MRP0

With Real-Time Query
sour_ludo sour_vico
sour_RW
CLIENTS
MRP0
sour_RO
UPDATES READS
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
SQL> ALTER DATABASE OPEN;
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;

Real-Time Query use case: reader farms
PRIMARY
REP1 REP2 REP3
REP4
REP5
REP6
UPDATES
READS

Real-Time Query: Support for GTTs
UNDO
TBS
TEMP
TBS
TEMP_UNDO_ENABLED = TRUE
GLOBAL
TEMPORARY
TABLE
DATA
TBS
SYSTEM
TBS
DATA &
UNDONew in
12c

Real-Time Query: Support for sequences
ASKS FOR A SET OF USABLE
SEQUENCES
PRIMARY STANDBYNew in
12c
It works only if CACHE and NOORDER are set
It does not work on cascade standbys

Take Away
You already pay Enterprise Licenses for the Primary and the Stanby
8CPUs8CPUs
APP Writes
Non Off-loadable Reads
Off-loadable (non-critical) Reads
380K$

Take Away
8CPUs8CPUs
APP Writes
4CPUs4CPUs
380K$
236K$

Take Away
8CPUs8CPUs
APP Writes
4CPUs4CPUs
4CPUs4CPUs
4CPUs
380K$
354K$
236K$

Take Away

Corrupted Blocks on Primary
sour_ludo sour_vico
sour_RW
CLIENTS
MRP0
sour_RO
CORRUPT BLOCK!

sour_ludo sour_vico
sour_RW
CLIENTS
MRP0
sour_RO
AUTOMATICALLY
FIND THE GOOD COPY

sour_ludo sour_vico
sour_RW
CLIENTS
MRP0
sour_RO
(Who said FISH & CHIPS?)
AUTOMATIC SHIP AND FIX!

Corrupted Blocks on Standby

Corrupted Blocks on Standby: you got the point, right?

Fast Incremental Backup
On Standby
(11g)

Block Change Tracking on Primary only
BCT
Incremental Backup on Primary: FAST

Block Change Tracking on Primary only
BCT
Incremental Backup on Primary: FAST Incremental Backup on Standby: SLOW

Block Change Tracking on Primary and Standby
BCT
Incremental Backup on Primary: FAST Incremental Backup on Standby: FAST
BCT

Advanced topologies:
Real-time Cascading Standby
(12cR1)

Real-Time Cascading Standby
PRIMARY CASCADING CASCADED

Real-Time Cascading Standby
SYNC, FASTSYNC or
ASYNC (LGWR)
ASYNC (LGWR)
<none> (ARCH)
Cascade supported by the broker
introduced in 12c

Real-Time Cascading Standby - «RedoRoutes»
PROD
DR
REP
RedoRoutes=‘(LOCAL : DR)’
RedoRoutes=‘ (PROD : REP ASYNC) (REP : PROD ASYNC)
(LOCAL : REP , PROD)’
RedoRoutes=‘(LOCAL:DR)’

Real-Time Cascade use case: again reader farms!
PRIMARY
REP1 REP2 REP3
REP4
REP5
REP6
UPDATES
READS

Real-Time Cascade use case: again reader farms!
PRIMARY
REP1 REP2 REP3
REP4
REP5
REP6
SYNC
UPDATES
READS

Far Sync Standby
(12cR1)

High distances = High latencies
Too far to support SYNC
redo-transport
ASYNC ONLY!!

Without Active Data Guard
ASYNC REMOTE
SYNC
LOCAL

With Active Data Guard
FAR_SYNC
Instance
SYNC
LOCAL
ASYNC
REMOTE

FAR_SYNC instance characteristics
Special controlfile
– ALTER DATABASE CREATE FAR SYNC INSTANCE CONTROLFILE;
NO datafiles and NO redo-apply
Standby logs are written and archived
The redo stream is redirected to the standby
Can’t be opened or converted to standby or primary

Example: one FAR_SYNC for each location
SYNC
LOCAL
FS_PROD
FS_DRPROD
DR
REP
ASYNC
REMOTE

Example: one FAR_SYNC for each location
SYNC
LOCAL
ASYNC
REMOTE
FS_PROD
FS_DRPROD
DR
REP

Enhanced Alternate Destinations
(12cR2)

Enhanced RedoRoutes
PROD
DR
REP

Enhanced RedoRoutes
PROD
DR
REP
!

Enhanced RedoRoutes
PROD
DR
REP
RedoRoutes=‘(LOCAL : (DR PRIORITY=1, REP PRIORITY=2))’
RedoRoutes=‘(LOCAL:(DR PRIORITY=1, PROD PRIORITY=2))’

(12cR1)

Oracle Active Data Guard 12cR2. Is it the best option?
For temporary recoverable outages
Transaction Guard – server side component
– Records transaction state within database
– Available with Oracle 12c Enterprise Edition.
Oracle 12c JDBC Replay Driver – client side component
– Replays the failed request.
– In 12.1 only for JDBC thin client, in 12.2 also OCI and ODP.net.
Requires RAC or RAC One Node or ADG (GG) option.
12/2/201754

Oracle Active Data Guard 12cR2. Is it the best option?
Example AC/TG interaction with UCP
1
Check-out connection
(Request begin)
Associate LTXID
Send LTXID to the driver
2
3
Work: INS/DEL/UPD/COM
INS
DEL
UPD
COM
Replay Buffer
4
Communication
Break
5
Recoverable Error
SQL Exception
8
Check the last LTXID
outcome
7
If safe, Replay
6
Request new connection
9
Check-in connection
(Request end)
UCP
12/2/201755
Runtime
Re-ConnectReplay

Transparent Application Continuity
(18c)

TAC: Application Continuity at the server side

(easier) Rolling Upgrades

Automatic steps with DBMS_ROLLING!
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)

SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
DBMS_ROLLING.
START_PLAN

SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
DBMS_ROLLING.
START_PLAN
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
Manual
upgrade

SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
DBMS_ROLLING.
START_PLAN
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
Manual
upgrade
SALES_ZH
(logical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
DBMS_ROLLING.
SWITCHOVER

SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
DBMS_ROLLING.
START_PLAN
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
Manual
upgrade
SALES_ZH
(logical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
DBMS_ROLLING.
SWITCHOVER
SALES_ZH
(logical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
Manual
upgrade

SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(physical SB)
T
R
A
I
L
I
N
G
L
E
A
D
I
I
N
G
DBMS_ROLLING.
INIT_PLAN(SALES_LS)
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
DBMS_ROLLING.
START_PLAN
SALES_ZH
(primary)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(logical SB)
Manual
upgrade
SALES_ZH
(logical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
DBMS_ROLLING.
SWITCHOVER
SALES_ZH
(logical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
SALES_ZH
(physical SB)
SALES_BS
(physical SB)
SALES_BE
(physical SB)
SALES_LS
(primary)
Manual
upgrade
DBMS_ROLLING.
FINISH_PLAN

What if you have to do it manually?
https://docs.oracle.com/database/121/SBYDB/dbms_rolling_upgrades.htm#SBYDB5230
SQL> SELECT instid, target, phase, description FROM DBA_ROLLING_PLAN;
INSTID TARGET PHASE DESCRIPTION
------ ------------ ------- -----------------------------------------------------
1 seattle START Verify database is a primary
2 seattle START Verify MAXIMUM PROTECTION is disabled
3 boston START Verify database is a physical standby
4 boston START Verify physical standby is mounted
...
93 oakland SWITCH Stop media recovery
94 seattle SWITCH Synchronize plan with new primary
95 seattle FINISH Verify only a single instance is active
96 seattle FINISH Verify database is mounted
...
111 oakland FINISH Wait until upgrade redo has been fully recovered
112 seattle FINISH Drop guaranteed restore point DBMSRU_INITIAL
113 boston FINISH Drop guaranteed restore point DBMSRU_INITIAL
114 oakland FINISH Drop guaranteed restore point DBMSRU_INITIAL
115 atlanta FINISH Drop guaranteed restore point DBMSRU_INITIAL

Local Data Services (Active Data Guard, no Clustware)
PRIMARY STANDBY
SERVICE_A_RO
CREATE OR REPLACE TRIGGER service_a_ro
after startup on database
DECLARE
role VARCHAR(30);
BEGIN
SELECT DATABASE_ROLE INTO role FROM V$DATABASE;
IF role = 'PRIMARY' THEN
DBMS_SERVICE.START_SERVICE(service_a');
ELSE
DBMS_SERVICE.START_SERVICE(service_a_ro');
END IF;
END;
/DB_SITE1 DB_SITE2
SERVICE_A_RW

Local Data Services (MAA, Active Data Guard, etc.)
Create services for Primary role on ALL the databases
Create services for Standby role on ALL the databases
Define connection descriptors with static address list

Local Data Services: not for complex environments
PRIMARY STANDBY STANDBY
STANDBY
SYNC
ASYNC
ASYNC

STANDBY
SYNC
ASYNC
ASYNC
SWISS
CLIENTS
READ
HERE
GERMAN
CLIENTS
READ
HERE

STANDBY
SYNC
ASYNC
ASYNC
IN CASE OF
LAG BOTH
READ HERE

STANDBY
SYNC
ASYNC
ASYNC
IN CASE OF
PROBLEMS ALL
READ FROM
PRIMARY

Global Data Services – Big Picture
Global Service
Manager 1
Global Service
Manager 2
Global Service
Manager 3
Global Service
Manager 4
SALES SALESSALES SALES SALESSALES
Golden Gate, Active Data Guard, Streams, […]
GDS POOL: SALES (sales_rw, sales_ro, sales_rep, …)
GDS
CATALOG
GDS
CATALOG

Global Data Services – How it works?
SALES SALES SALESSALES
GSM03 GSM04
GDS Region: SWITZERLAND
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
Request a connection for a global service to a GSM
Service naming: <gs_name>.<gds_pool>.<gds_configuration>
1

GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1 2
GSM returns the local listener address (SCAN is bypassed)
1
2

GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1 2
3
GSM returns the local listener address (SCAN is bypassed)
Connect to the Global Service active locally on the target
1
2
3

Global Database Services - Features
Global Data Services support
– Local Service Attributes (TAF, rlbgoal, clbgoal, commit outcome…)
– Preferred and available databases
– Replication lag threshold (ADG only)
– Region affinity

Global Connection Region Affinity - Anywhere
GDSCTL> ADD SERVICE -gdspool sales
-service sales_rpt -locality ANYWHERE
SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
SALES SALES

Global Connection Region Affinity - Anywhere
-service sales_rpt -locality ANYWHERE
SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
SALES SALES
1
REMOTE
LOCAL

Global Connection Region Affinity – Local Only
-service sales_rpt -locality LOCAL_ONLY
SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
SALES SALES

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
SALES SALES
LOCAL

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
2
SALES SALES
LOCAL
CRASH

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
2
3
SALES SALES
LOCAL
CRASH
TNS-12514

Global Connection Region Affinity – Region Failover
-service sales_rpt -locality LOCAL_ONLY –region_failover
SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
SALES SALESSALES SALES

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
LOCAL

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
2
LOCAL
CRASH

SALES SALES
GSM03 GSM04
GSM01 GSM02
GDS Region: GERMANY
DATABASE CLIENTS
1
2
3
LOCAL
CRASH
REMOTE

Role-Based Global Services – Lag Tolerance
Role-based services are supported for pool databases in Data Guard Broker configuration
GDSCTL> ADD SERVICE -gdspool <gds_pool> -service <service>
[ -role PRIMARY |
-role PHYSICAL_STANDBY -failover_primary –lag 20
DB1 DB2
PRIMARY
DB3
1 STANDBY STANDBY

[ -role PRIMARY |
DB1 DB2
PRIMARY
DB3
1
2
STANDBY STANDBY
STANDBYPRIMARYSTANDBY

[ -role PRIMARY |
DB1 DB2
PRIMARY
DB3
1
2
STANDBY STANDBY
3 STANDBYPRIMARYSTANDBY
LAG>20

[ -role PRIMARY |
DB1 DB2
PRIMARY
DB3
1
2
STANDBY STANDBY
3
4
STANDBY
STANDBY
PRIMARYSTANDBY
LAG>20

[ -role PRIMARY |
DB1 DB2
PRIMARY
DB3
1
2
STANDBY STANDBY
3
4
STANDBY
STANDBY
PRIMARYSTANDBY
LAG>20
PRIMARYSTANDBY STANDBY
LAG<=20
5

So?

Take aways
You pay for your standby: with Active Data Guard you can increase the ROI
You use Active Data Guard for real-time query? There is more!
One standby uses ADG, the others no? License just that server!
If you have Golden Gate, you already have ADG. Use it!

12/2/2017 Oracle Active Data Guard 12cR2. Is it the best option?95
Technology on its own won't help you.
You need to know how to use it properly.

Trivadis @ DOAG 2017
#opencompany
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Oracle Active Data Guard 12cR2. Is it the best option?

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