Understanding Oracle RAC 12.1.0.2 Internals the Cache Fusion Edition

8/19/2019 Understanding Oracle RAC 12.1.0.2 Internals the Cache Fusion Edition

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Copyright © 2014, Oracle and/or its affiliates. All rights reserved.

Safe Harbor StatementThe following is intended to outline our general product direction. It is inteninformation purposes only, and may not be incorporated into any contract.commitment to deliver any material, code, or functionality, and should not in making purchasing decisions. The development, release, and timing of anfunctionality described for Oracle’s products remains at the sole discretion


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Three Alternative Architectures – The Same Idea A


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Three Alternative Architectures – The Same Idea A


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Program Agenda

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Cache Fusion Overview

(Dynamic Re-) Mastering

Handling Contentions

RAC Meets Multitenant

RAC Meets In-Memory

Oracle Confidential – Inte


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Program Agenda

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RAC Meets In-Memory



9/36Copyright © 2014, Oracle and/or its affiliates. All rights reserved.

• Requester

• Listener

• Service

• Holder

• Master

• Session

Oracle RAC Combines it All & Adds Services

I

ot



• In an Oracle environment, list

establish connections with an i

• In an Oracle RAC environmenof listeners are used (for this p

1. SCAN and SCAN Listener

2. Local Listeners per node

• Services are used to load bal

• Local listeners will establish on instances where the servi

• Once a session is establishedinstance, the sessions stays u

Listeners and Services Direct Work to an Instance



• Local Cache Hit

• Access time: nanoseconds

• Remote Cache Hit

• Access time: microseconds

• Data is on disk

• Flash cache acce

• Disk controller ca

• Spinning disk acc

Getting Access to Data

Whether local or remote, cache hits are alwaysfaster than reading from spinning disks


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Case 1 (all local)

• All entities in one instance

• Data holding instance

• Session “holding” instance

• Mastering Instance

Case 2 (local / remote)

• Some entities in one instance

•Data holding instance

• Session “holding” instance

• Two way communication

Case 3 (all distributed

• All entities are dispers

• Three way communicato obtain a given block o

• Message operatioimprovements sin

Maximum Three Way Communication

write write

Message

Block


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Dynamic Retrieval of Data

+ +

2

3

1

• In order to fulfill a given requesOracle RAC can decide to:

• Assemble data spread across inst

• Perform a (full) disk read for (part

• Use assembly and (full) disk reads

• The decision which access pathdependent on various factors (enetwork utilization)

• Respective parameters are monit

• The access path can changeaccordingly and dynamically.

Once data has been shipped to an insthe cache for further (local) access

communicated as required (via


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Program Agenda

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RAC Meets In-Memory



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• In Oracle RAC, every object is mastered (aspart of Global Cache Services / GCS) by aninstance.

• The Global Resource Directory (GRD) isused to “keep track” of mastering.

• Illustration above is symbolic for this matter.

• If a session requests write accessto a block that is not mastered bythe instance hosting the session,the master instance needs to becontacted (via message).

• Based on user acceRe-Mastering (DRM)changing the masterinstance to another.

• Relocating the maswhere data is requesmessaging.

Mastering and Dynamic Re-Mastering

germanyOracle GI | HUB

Oracle RAC

argentinaOracle GI | HUB

Oracle RAC

brazilOracle GI | HUB

Oracle RAC

germany Oracle GI | HUB

Oracle RAC


Oracle RAC

brazil Oracle GI | HUB

Oracle RAC

write


Oracle RAC

argenOrac

Ora


Oracle RAC

argenOrac

Ora


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• DRM is used internally and exte

•

Externally means access patterninfluence the mastering of user d

• Internally DRM is used for the manof UNDO data across instances for e

• DRM activity is also performed upinstances leaving or joining the clus

• Do not turn DRM off (_gc_polic

• Optimize _gc_policy_minimum at a convenient moment under n

• Consider using smaller SGA size

• See MOS note 1619155.1 – “Best PRecommendations for RAC databaslarger than 300GB” as applicable

• “dbms_cacheutil” can be used to mrelease affinity under well understo

Dynamic Re-Mastering (DRM) – Recommendation


Oracle RAC


Oracle RAC

brazil Oracle GI | HUB

Oracle RAC

write


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• The Cache Fusion Accelerator (C

• OS kernel (Linux & Solaris only

• which can respond directly tocertain lock requests via RDSv3

• The lock state is saved in memoby the database and the kernel.

• CFA saves user/kernel context sCPU cycles in LMS, and “speeds u

• CFA will be activated on Engine

time, including the Oracle Databa

• CFA contributes to a better, line

• CFA is one of a long list of impro

New in 12.1.0.2: Cache Fusion Accelerator

germanyOracle GI

Oracle RAC

argentinaOracle GI

Oracle RAC

brazilOracle GI

Oracle RAC

write

LMS process Accelerator

Lock grant


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New in 12.1.0.2: Cache Fusion Accelerator

germanyOracle GI

Oracle RAC

argentinaOracle GI

Oracle RAC

brazilOracle GI

Oracle RAC

write

LMS process Accelerator

• The Cache Fusion Accelerator (C

• OS kernel (Linux & Solaris only

• which can respond directly tocertain lock requests via RDSv3

• The lock state is saved in memoby the database and the kernel.

• CFA saves user/kernel context sCPU cycles in LMS, and “speeds u

• CFA will be activated on Engine

time, including the Oracle Databa

• CFA contributes to a better, line

• CFA is one of a long list of impro


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Program Agenda

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5





RAC Meets In-Memory



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writewrit

• Contention can occur in any multi-user system (even in SI databases)

• User data as well as “metadata” (e.g.an index) can be subject to contention

• You can still guide users to only oneinstance in an Oracle RAC environment.

• As soon as you scale out, contentioncan occur between instances (not onlywithin an instance).

• From a contention setup is basically thenodes setup.

• The difference is inbased communicatioconsidering the mas

How To Handle Contention – Basicswrite

writewrite

write

writewrite

writewrite

Note: for scalability, only write/write contention needs to be considered


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• Frequent transactional changes to thesame data blocks in all instances mayresult in “write hot spots”.

• Block with pending changes maybe “pinged” by other instances.

• Pending redo must be written to logbefore the block can be transferred

• Latency for a deferred block transferbecomes dependent on delay for log IO

• Contention can affemuch as it can affect

• Right growing indeindex contention are

• In 99% of OLTwrite hot spots

How To Handle Contention – Considerationswrite

writewrite

write

writewrite

writewrite

REDO


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• Avoid frequent transactional changesto the same data blocks in all instancesusing partitioning and services.

• Logically partition data so that sub-data is handled in one instance only.Guide users via services accordingly.

• Place redo logs on fast storageif performance critical; e.g. SSDs

•Implemented in 11.2.2.4 of Exadata and OracleDatabase Appliance by default (Smart Logs andSSDs, respectively)

•Separate disks for logs from other IO busy disks

• Use either for b

• Global hash

• Locally parti

• Drop unused in

How To Handle Contention – General Solutionswrite

writewrite

write

REDO

writewrite

writewrite

Get the best out of Oracle Partitioning - A practical guide and reference

https://www.slideshare.net/secret/nHJV1CjWWOlGOl

https://www.slideshare.net/secret/nHJV1CjWWOlGOlhttps://www.slideshare.net/secret/nHJV1CjWWOlGOl


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• UCP supports “Connection Affinity”:

• Transaction-Based Affinity

• Web Session Affinity

http://docs.oracle.com/database/121/JJUCP/rac.htm#JJUCP8197

• Connection Pools limit the numberof connections to the database – example:

• Oracle Universal Connection Pool (UCP)

• Use “Database Resident ConnectionPooling” when no. of active sessionsmuch smaller then no. of open session.

• Fast Application – enabled conneLoad Balancing inthe Workload Reper-service basis

How To Handle Contention – Use Connection Poolwrite

writewrite

writewrite

writeConnection PoolConnection Pool Conn

busy

http://docs.oracle.com/database/121/JJUCP/rac.htmhttp://docs.oracle.com/database/121/JJUCP/rac.htmhttp://docs.oracle.com/database/121/JJUCP/rac.htm


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Program Agenda

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RAC Meets In-Memory



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•Pluggable Databases (PDBs) represent themselves as services in anOracle RAC Multitenant Database, ensuring extremely fast failover.

• PDBs can be used to conveniently align users to instances withall the benefits, providing higher consolidation benefit and agility.

• Oracle RAC Multitenant Databases h

• Future improvements will ensure gre

• Multithreaded Redo Log writer alre

Oracle Multitenant and Oracle RAC – a Symbiosis

germany

Oracle GI | HUB

Oracle RAC

argentina

cons_1

REDO


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•Pluggable Databases (PDBs) represent themselves as services in anOracle RAC Multitenant Database, ensuring extremely fast failover.

• PDBs can be used to conveniently align users to instances withall the benefits, providing higher consolidation benefit and agility.

Oracle Multitenant and Oracle RAC – a Symbiosis

germany

Oracle GI | HUB

Oracle RAC

argentina

cons_1

REDO

• Oracle RAC Multitenant Databases help

• Future improvements will ensure great

• Multithreaded Redo Log writer alread

• Per-PDB/service optimized GCS operat

More information, see: Oracle Multitenant meets Oracle RAC -http://www.slideshare.net/MarkusMichalewicz/oracle-

multitenant-meets-oracle-rac-ioug-2014-version

http://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-versionhttp://www.slideshare.net/MarkusMichalewicz/oracle-multitenant-meets-oracle-rac-ioug-2014-version


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Program Agenda

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RAC Meets In-Memory



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Oracle In-Memory and Oracle RAC

Breakthrough:Dual Format

Database

GenerateReportsInstantly

ColumnStore

ReplacesAnalyticIndexes

In-Memory

Column Store

Full HA &Integration

withIndustry

Standards


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Oracle In-Memory and Oracle RAC – A Dream-Team

In-Memory

Column Store

Addresses

Addresses

Breakthrough:Dual Format

Database

ColumnStore

ReplacesAnalyticIndexes


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“Full support for RAC scale-means Oracle Database In-can be used on our largestWarehouse, enabling morereal-time analytics.”

– Sudhi Vijayakumar, Senior Oracle Yahoo Inc.


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Oracle Database In-Memory: Unique Fault Toleran

•

Similar to storage

• Duplicate in-memcolumns on anoth

• Enabled per ta

• Application tran

• Downtime eliminausing duplicate a

Only Available on Engineered Systems


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“Downtime is extremely cosbusiness. Oracle’s In-Memarchitecture takes the righto balancing real-time speecontinuous availability.”

– Jens-Christian PokolmAnalyst IT-DB Architecture & EngiPostbank Systems AG


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• In-Memory compresses data,optimizing the use of memory.

• Memory allocated for In-Memoryis subject to simplified lock mgmt.

• In-Memory Speed and Capacity ofLow Cost Disk

• PCI Flash works m

• Shared solutionsRAC external sync

• Coming soon on integrated shared

Optimized Used of Memory in Every Layer

NormalBuffer Cache

In-MemoryFormat

NormalBuffer Cache

In-MemoryFormat

• Compressed• Lock mgmt.

simplified

germany

Oracle GI | HUB

Oracle RAC

argen

Orac

Ora

?

C


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• Database and Middleware streams available

•

Videos – Feature different groups and presenters

– Cover a broad range of topics and products

• FREE OF CHARGE Oracle RAC PM / Dev contributions:

– Oracle Flex Cluster: Optimized Resource Management for the Cloud - Ian Cookson

– Oracle Grid Infrastructure 12c Bundled Agents – Shankar Iyer

– ACFS Product Overview and Use Cases - Ara Shakian

– The Oracle Real Application Clusters (RAC) Family of Solutions - A User Guide – Markus Micha

– Next Generation Oracle Automatic Storage Management - Jim Williams

– Implementing DBaaS with Oracle RAC 12c and Quality of Service Management - Mark Scardin

– Oracle RAC Practical Performance Management and Tuning – Markus Michalewicz

Oracle Learning Streams: http://education.oracle.com/st

http://education.oracle.com/streams/http://education.oracle.com/streams/


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Understanding Oracle RAC 12.1.0.2 Internals the Cache Fusion Edition

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