Ahmet Fuat – Bahçe ş ehir University İleri Seviyede Oracle Ön Bellek Mekanizması (Oracle Coherence)

Who am i Y.T.U – Computer Engineering I.T.U – Computer Engineering, not completed Since 2008, Turkcell

Agenda  What is the cache and buffer?  Why we use caches in designing programming?  Oracle Coherence  Features  Demos  Final

Buffer Memory  A buffer is a region of a physical memory storage used to temporarily hold data while it is being moved from one place to another.  It is a temporary memory location that is traditionally used because CPU instructions cannot directly address data stored in peripheral devices.

Caching  A cache is a component that transparently stores data so that future requests for that data can be served faster.

Caching  CPU Cache  TLB ( Translation Lookaside Buffer )  Disk Cache  Web Cache  DNS Cache

Cache in Programming EMP_IDNAMETEL_NO ADDRESSGENDER İ stM İ stanbulM İ stanbul M DB EMP_IDNAMETEL_NOGENDER 1Ahmet531232M 3Hasan855412M request response responseresponse requestrequest

Oracle Coherence  A variety of caching strategies  Reporting and administrator support via JMX and associated tools  Rich language support via Coherence*Extend  Has no single point of failure  Automatically and transparently fails over and redistributes its clustered data managements services.  Automatically scale up your application when a server added

What is Coherence Cluster Node  A Coherence Cluster node  Sometimes referred to as a member or cluster member  Is a java process  Joins a cluster  Is an instance of Coherence server  Can contain data, run processing and serve events  Is often defined by a cache configuration  localstorage.enabled = true => node contains data JVM 1 PID : 5654 NODE 1 JVM 2 PID : 5655 NODE 2 JVM 3 PID : 5656 NODE 3

Clustering in Coherence  Using a conference room model  -Dtangosol.coherence.cluster=name  Listening  Discovery  Working Groups and Private Conversation  Death detection  Failed Servers  Failover  Failback

Coherence Cache Topology Examples  Local Cache  Replicated Cache JVM Local Cache JVM Replicated Cache JVM Replicated Cache JVM Replicated Cache

Coherence Cache Topology Examples  Partitioned Cache ( Distributed Cache )  Near Cache JVM Partitioned Cache JVM Local Cache JVM Partitioned Cache

Replicated Cache Animation CUST_IDNAMETEL_NO 1Ahmet Sungur Ay ş e Öz ,2 Add a customer 3Mehmet Akar ,2 3 Seamlessly get all cache data and put into in its own cache

Partitoned Cache Animation CUST_IDNAMETEL_NO 1Ahmet Sungur Ay ş e Öz Add a customer 3Mehmet Akar

Near Cache Animation requests 1 from Front cache returns 1 from front cache no need to access back cache 34 requests 2 from Front cache it’s need to access back cache returns 2 from back cache and write it to front cache 2 returns 2 to app From front cache Generally, Local Cache is used for front cache, because of ~0 cost Generally, Partitioned Cache is used for back cache, because of accessing much more data.

Near Cache Animation Updates 2 to Front cache 2 Near Cache invalidation strategies  Listen None  Listen Present  Listen All  Listen Auto

Failover

When data source is involved Read-Through Write-Through Write-Behind Refresh-Ahead Caching

Read Through Caching

Write Through Caching

Write-Behind Caching  Improves application performance  Reduces database load  Insulated from database failures  Linear Scalibility

Refresh-Ahead Two parameters Expiration time Refresh-ahead factor Expiration time:60 seconds Refresh Ahead factor :0.5 Database CUST_IDNAMETEL_NOEXPIRATI ON_TIME 1Ahmet Sungur :45:48 2Ay ş e Öz :45:24 Request 48-10>60*05, So no need to reload Request 24-15<60*05 So we need to reload Get object 2 from db put into the cache Got fresh object from db ( obj 2 ) 13:46:15

Event and Parallel Processing  Coherence supports two background processing models  Parallel Processing  Events  Map listeners which are called asynchronously after data changes  Map triggers which are called synchronously before data changes

Queries and Filters  Coherence supports two query mechanism  A filter mechanism, useful for events and event filters  MapEventFilter  AndFilter, OrFilter  …  A SQL-Like mechanism known as the Coherence Query Language useful for queries against caches  SELECT result-set | * FROM cache-name WHERE conditional-expression  Select * from customers where name like ‘%ap%’  Select max(price) from stocks where lastupdatedate  Select avg(price) from stocks  Insert, update, delete…

Demo Time Oracle Virtual Box 4.1 Oracle Enterprise Linux OEPE ( Oracle Enterprise Package for Eclipse ) Oracle Coherence 3.7.1

Other Coherence Security Coherence Management Managing and monitoring via JMX Coherence Reporter Coherence*Extend Coherence*Web

Summary