birt upc-a

birt upc-a

birt upc-a

birt upc-a

birt upc-a,

birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,

birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,

birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,

birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,
birt upc-a,

Oracle provides several memory management methods, as summarized here: Automatic memory management: This new option in Oracle Database 11g lets the database manage the SGA and PGA components of memory completely automatically. Automatic shared memory management: This option automates the management of the SGA but not the PGA. Automatic PGA memory management: This option automates just the PGA memory. Manual shared memory management: You set the sizes of the individual components of the SGA such as the shared pool and the buffer cache. Manual PGA memory management: You set the PGA memory manually. Oracle recommends that you use automatic memory management, under which the database dynamically adjusts the levels of the individual SGA components as well as the PGA allocations.

2. Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software (Boston: Addison-Wesley Professional, 1995).

The database will redistribute memory from the SGA to the PGA and vice versa, depending on what s needed. Your job is to set the initial level of memory you want to allocate to the database and then let the database handle the day-to-day management of that memory.

As of this writing, the Linux, Solaris, Windows, HP-UX, and AIX platforms support automatic memory management.

You can enable automatic memory management when creating a database through the Database Configuration Assistant (DBCA) The DBCA offers you a choice of automatic memory management and other types of memory management You can set the initialization parameters that control automatic memory management by using the Memory tab of the Initialization Parameters page Select automatic memory management by checking the Use Automatic Memory Management box in the Typical section In order to switch to automatic memory management, you must set the MEMORY_TARGET parameter, which sets the target memory for the instance You can also set the maximum memory size for an instance by specifying a value for the MEMORY_MAX_TARGET initialization parameter.

The notification procedure call can carry an arbitrary number of parameters. By convention, a single parameter is used, derived directly or indirectly from class EventObject, which has a field that references the event source. Figure 5-7 shows a custom event type called MyCustomEvent. JavaBeans event sources publish events by using a special naming convention. For example, given an event of type MyCustomEvent, the source must have two public methods named addMyCustomListener and removeMyCustomListener to add and remove listeners, respectively. JavaBeans development tools use reflection on classes to find events, based on the naming convention. Listing 5-10 shows how you might implement class MyEventSource. Listing 5-10. A Simple JavaBeans Event Source public class MyEventSource{ MyCustomListener listener; public synchronized void removeMyCustomListener(MyCustomListener l) { if (listener == l) listener = null; } public synchronized void addMyCustomListener(MyCustomListener l) { listener = l; } protected void fireMethod1(MyCustomEvent e) { if (listener != null) listener.method1(e); } public void testMyCustomEvent() { MyCustomEvent e = new MyCustomEvent(this); fireMethod1(e); } } In order to support multicasting, an event source must use a collection to store references to multiple listeners. When firing an event, the event source must iterate over the listeners in the collection. Listing 5-11 shows how MyEventSource might look when supporting multicast MyCustomEvents. Listing 5-11. A JavaBeans Event Source with a Multicast Event public class MyEventSource { private Vector myCustomListeners = new Vector( ); public synchronized void removeMyCustomListener(MyCustomListener l) { if (myCustomListeners.contains(l)) myCustomListeners.removeElement(l); }

Before you can allocate the appropriate amount of memory you should assign to the database under the new automatic memory management feature, you must first find out how much memory the database is currently using for its SGA and PGA memory allocations Your goal is to allocate an amount of memory that s about the same as the sum of the SGA and PGA memory that the database currently consumes However, this doesn t mean that you can simply sum up the values of the SGA_TARGET and PGA_TARGET parameters to arrive at the total memory requirements of the database The reason for this is that unlike in the case of the SGA_TARGET parameter, the database doesn t immediately take over the memory you assign for the PGA_TARGET parameter The database only bases its PGA allocation to each session on the value for the PGA_TARGET parameter.