Transactional Collocation Optimization for Collocated Objects
5.2.6.1 Transactional Collocation
As an extension to the basic collocation strategy, WebLogic Server attempts to use collocated clustered objects that are enlisted as part of the same transaction. When a client creates a UserTransaction object, WebLogic Server attempts to use object replicas that are collocated with the transaction. This optimization is depicted in the example shown in Figure 5–5 . Load Balancing in a Cluster 5-11 Figure 5–5 Collocation Optimization Extends to Other Objects in Transaction In this example, a client attaches to the first WebLogic Server instance in the cluster and obtains a UserTransaction object. After beginning a new transaction, the client looks up Objects A and B to do the work of the transaction. In this situation WebLogic Server always attempts to use replicas of A and B that reside on the same server as the UserTransaction object, regardless of the load balancing strategies in the stubs for A and B. This transactional collocation strategy is even more important than the basic optimization described in Section 5.2.6, Optimization for Collocated Objects. If remote replicas of A and B were used, added network overhead would be incurred for the duration of the transaction, because the peer connections for A and B would be locked until the transaction committed. Furthermore, WebLogic Server would need to employ a multi-tiered JDBC connection to commit the transaction, incurring additional network overhead. By using collocating clustered objects during a transaction, WebLogic Server reduces the network load for accessing the individual objects. The server also can make use of a single-tiered JDBC connection, rather than a multi-tiered connection, to do the work of the transaction.5.3 Load Balancing for JMS
WebLogic Server JMS supports server affinity for distributed JMS destinations and client connections. By default, a WebLogic Server cluster uses the round-robin method to load balance objects. To use a load balancing algorithm that provides server affinity for JMS objects, you must configure the desired method for the cluster as a whole. You can configure the load balancing algorithm by using the Administration Console to set weblogic.cluster.defaultLoadAlgorithm. For instructions, see Section 10.2.5, Configure Load Balancing Method for EJBs and RMIs.Parts
» Oracle Fusion Middleware Online Documentation Library
» Document Scope and Audience Guide to this Document
» What Are the Benefits of Clustering? What Are the Key Capabilities of a Cluster?
» Servlets and JSPs EJBs and RMI Objects
» Getting Connections with Clustered JDBC Failover and Load Balancing for JDBC Connections
» Pure-Java Versus Native Socket Reader Implementations
» Client Communication via Sockets
» How WebLogic Server Creates the Cluster-Wide JNDI Tree
» How WebLogic Server Updates the JNDI Tree Client Interaction with the Cluster-Wide JNDI Tree
» Load Balancer Configuration Requirements Load Balancers and the WebLogic Session Cookie
» Related Programming Considerations How Session Connection and Failover Works with a Load Balancer
» Round-Robin Load Balancing Weight-Based Load Balancing
» Transactional Collocation Optimization for Collocated Objects
» Methods of Configuring Clusters Load Balancing for JDBC Connections
» Using Replication Groups HTTP Session State Replication
» Connection with Load Balancing Hardware Failover with Load Balancing Hardware
» Configuration Requirements for Cross-Cluster Replication
» Configuring Session State Replication Across Clusters
» Clustering Objects with Replica-Aware Stubs
» Failover and JDBC Connections Understanding Server and Service Migration
» Migration Terminology Oracle Fusion Middleware Online Documentation Library
» Features That Use Leasing Leasing Versions
» Determining Which Type of Leasing To Use High-availability Database Leasing
» Non-database Consensus Leasing Leasing
» Preparing for Automatic Whole Server Migration
» Configuring Automatic Whole Server Migration
» Startup Process in a Cluster with Migratable Servers
» Automatic Whole Server Migration Process
» Manual Whole Server Migration Process Administration Server Role in Whole Server Migration
» Migratable Server Behavior in a Cluster Node Manager Role in Whole Server Migration
» Cluster Master Role in Whole Server Migration
» JMS-related Services JTA Transaction Recovery Service
» Custom Store Availability for JMS Services Default File Store Availability for JTA
» Best Practices for Targeting JMS when Configuring Automatic Service Migration
» Architecture Web Application Tiers
» Combined Tier Architecture De-Militarized Zone DMZ Load Balancer Proxy Plug-In
» No Collocation Optimization Firewall Restrictions
» Multi-Tier Proxy Architecture Proxy Architecture Benefits Proxy Architecture Limitations
» Proxy Plug-In Versus Load Balancer
» DMZ with Two Firewall Configuration
» Dynamic Cluster Address If you do not explicitly define a cluster address
» Configuration Roadmap Install WebLogic Server
» Starting a WebLogic Server Cluster
» Configure Node Manager Configure Load Balancing Method for EJBs and RMIs
» Sample web.xml This section contains a sample deployment descriptor file
» Accessing Applications Via the Proxy Server Ensure that applications clients will
» Configure Replication Groups Configure Migratable Targets for Pinned Services
» Migrating When the Currently Active Host is Unavailable Use this migration
» Configure Multicast Time-To-Live TTL Configure Multicast Buffer Size
» Cluster-Related Configuration Options Follow Usage and Configuration Guidelines
» Manual Migration of the JTA Transaction Recovery Service State Management in a Cluster
» Naming Considerations Administration Server Considerations
» Firewall Considerations Avoiding Problems
» Check the Server Version Numbers Check the Multicast Address Check the CLASSPATH Value
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