Oracle WebLogic Server 12c Essentials

C: The saviour of having to type in the username and password each and every time that you start a server. A very useful little file to have, particularly if you have multiple managed servers.

By default, this appears in the Admin Servers security directory ($DOMAIN_HOME/servers/AdminServer/ security) when a domain is created in development mode and is called boot.properties. The file is only created for the admin server, not for any additional servers; simply copying the security directory over is
enough. The password is encrypted for the domain, so it can only be used for servers within that domain.

In production mode, the boot.properties file doesn't exist.

D: Development mode enables a WebLogic Server instance to automatically deploy and update applications that are in the domain_name/autodeploy directory (where domain_name is the name of a WebLogic Server domain). Production mode disables the auto-deployment feature and prevents any applications you place in the autodeploy directory after you switch to production mode from being deployed.

Note:
* By default, a WebLogic Server domain runs in development mode.

* You can run a WebLogic Server domain in two different modes: development and production. Only development mode allows you use the auto-deployment feature

E: Oracle Enterprise Pack for Eclipse 12c (12.1.1.2.1) Eclipse Based Enterprise Application Development Oracle Enterprise Pack for Eclipse (OEPE) 12.1.1.2.1 for Eclipse Juno provides tools that make it easier to develop applications utilizing specific Oracle Fusion Middleware technologies and Oracle Database.

Note:
* Support for IDE's. WebLogic already supported JDeveloper 11.1.1.5, but will come out with the 11.1.1.6 later on. Also suported are Eclipse and NetBeans 7.1 IDE. The JDeveloper 11.1.1.6 and IntelliJIdea IDE will be supported in a later timeframe.

fair-share-request-class--Specifies the average thread-use time required to process requests. The default fair share value is 50.

For example, assume that WebLogic Server is running two modules. The Work Manager for ModuleA specifies a fair-share-request-class of 80 and the Work Manager for ModuleB specifies a fair-share-request-class of 20. During a period of sufficient demand, with a steady stream of requests for each module such that the number requests exceed the number of threads, WebLogic Server will allocate 80% and 20% of the thread-usage time to ModuleA and ModuleB, respectively.

* Example:

<work-manager>
<name>lowpriority_workmanager</name>
<fair-share-request-class>
<name>low_priority</name>
<fair-share>10</fair-share>
</fair-share-request-class>
</work-manager>

<work-manager>
<name>highpriority_workmanager</name>
<fair-share-request-class>
<name>high_priority</name>
<fair-share>100</fair-share>
</fair-share-request-class>
</work-manager>

Note:
* A request class expresses a scheduling guideline that WebLogic Server uses to allocate threads to requests. Request classes help ensure that high priority work is scheduled before less important work, even if the high priority work is submitted after the lower priority work.

Incorrect:

Not C: response-time-request-class--Specifies a response time goal in milliseconds. Response time goals are not applied to individual requests. Instead, WebLogic Server computes a tolerable waiting time for requests with that class by subtracting the observed average thread use time from the response time goal, and schedules requests so that the average wait for requests with the class is proportional to its tolerable waiting time.

Not A, D: Not related to thread constraints.
For example, assume that WebLogic Server is running two modules. The Work Manager for ModuleA specifies a fair-share-request-class of 80 and the Work Manager for ModuleB specifies a fair-share-request-class of 20.

A:
* Troubleshooting Slow Response Time from the Client and Low Database Usage These symptoms are usually caused by a bottleneck upstream of the database, perhaps in the JDBC connectionpooling. Monitor
the active JDBC connections in the WebLogic Console and watch for excessive waiters and wait times;
increase the pool size, if necessary.

* Attribute: Maximum Capacity
Maximum number of physical database connections that this connection pool can contain. Different JDBC Drivers and database servers may limit the number of possible physical connections.

C: Attribute: Statement Cache Size
The algorithm used to maintain the statement cache:

LRU - After the statementCacheSize is met, the Least Recently Used statement is removed when a new statement is used.

Fixed - The first statementCacheSize number of statements is stored and stay fixed in the cache. No new statements are cached unless the cache is manually cleared.

E: If the queue appears starved but adding execute threads does not improve performance, there may be resource contention. Because CPU utilization is low, the threads are probably spending much of their time waiting for some resource, quite often a database connection. Use the JDBC monitoring facilities in the console to check for high levels of waiters or long wait times. Adding connections to the JDBC connection pool may be all that is required to fix the problem.

Note:
* If you had a JDBC connection pool where the Initial Capacity and Maximum Capacity attributes were different, you might want to create a gauge monitor to monitor the maximum and minimum number of connections.
By setting the Threshold Low value to be one less than the Initial Capacity, your gauge monitor trapcould monitor the ActiveConnectionsCurrentCount attribute of the JDBCDataSourceRuntime MBean and alert you whenever the number of active connections are less than the Initial Capacity (which might indicate database connectivity problems).

By default, JMS messages never expire. When applications send messages to queues or topics with durable subscribers, WebLogic must retain the message until it is consumed. This is fine in most point-to-point messaging applications because consumers are constantly consuming messages. Any message sent to a queue will typically be consumed in a relatively short period of time. If the consumers get disconnected, they will usually reconnect as soon as possible and start processing any messages that might have built up in the queue.

D: For durable subscribers to a topic, this is not necessarily true. The messaging system is forced to retain any message that has not been consumed by a durable subscriber, regardless of whether that durable subscriber will ever return. In this case, WebLogic is at the mercy of the durable subscriber to unsubscribe when it no longer wishes to receive the messages. If the durable subscriber logic is flawed in such a way that the subscribers do not unsubscribe properly, the messaging system will start to fill up with messages that may never be delivered. This calls for real caution in using durable subscribers. Fortunately, there is another way to help deal with this problem. Message expiration can be set at the connection factory level.
Using a connection factory's default time-to-live attribute, we can specify the number of milliseconds that WebLogic should retain an undelivered message after it is sent.

You can configure a JDBC TLOG store to persist transaction logs to a database, which provides the following benefits:

* Leverages replication and HA characteristics of the underlying database.

* Simplifies disaster recovery by allowing the easy synchronization of the state of the database and
TLOGs.

* Improved Transaction Recovery service migration as the transaction logs to do not need to be migrated (copied) to a new location.

* You can configure a JDBC TLOG store to persist transaction logs to a database, which allows you to leverage replication and HA characteristics of the underlying database, simplify disaster recovery, and
improve Transaction Recovery service migration.

incorrect:
not B: Read-only, One-phase Commit Optimization requires Oracle DB 11.1.0.7.3PSU or above.

B: A domain consists of one or more WebLogic Server instances (and their associated resources) that you manage with a single Administration Server.

D: In a domain, server instances other than the Administration Server are referred to as Managed Servers.
Managed Servers host the components and associated resources that constitute your applications.

Incorrect:
Not A: Each WebLogic Server domain must have one server instance that acts as the Administration Server.
Not C: A domain can include multiple WebLogic Server clusters and non-clustered WebLogic Server instances.

Not E: A Node Manager process is not associated with a specific WebLogic domain but with a machine.
You can use the same Node Manager process to control server instances in any WebLogic Server domain, as long as the server instances reside on the same machine as the Node Manager process. Node Manager must run on each computer that hosts WebLogic Server instances--whether Administration Server or Managed Server--that you want to control with Node Manager.

References:
Overview of WebLogic Server Domains

D: Elastic message overflow is the ability for WebLogic JMS to take advantage of solid state disks, especially on Exalogic, for paging of JMS messages. This is especially important in spikes of traffic.
Access to SSD is much faster than disks or the database, which are used for true persistent storage. This speed of writing and reading enables the system to absorb the spikes in traffic.

wls-maven-plugin--Delivered in WebLogic Server 12c, provides enhanced functionality to install, start and stop servers, create domains, execute WLST scripts, and compile and deploy applications.

References:
Developing Applications for Oracle WebLogic Server, Using the WebLogic Development
Maven Plug-In