Oracle 10G Chapter 1 Part Iii

Front 1

What is SGA?

Back 1

An Oracle Server Instance is made up of Oracle's main memory structure, called the System Global Area.
The Server Processes communicates with SGA when the user accesses the data in the database.

Front 2

What are the components of SGA?

Back 2

1-Shared Pool
2-Database Buffer Cache
3-Redo Log Buffer
4-Java Pool
5-Large Pool
6-Streams Pool

Front 3

Describe Shared Pool?

Back 3

Shared Pool caches the most recent SQL issued by the user.
It uses LRU (Least Recently Used algorithm)to manage the contents

Front 4

Describe Database Buffer Cache?

Back 4

Caches the data that has been most recently accessed by the users.
It uses LRU (Least Recently Used algorithm)to manage the contents

Front 5

Describe Redo Log Buffer?

Back 5

It stores information for the recovery process.

Front 6

Describe Large Pool?

Back 6

Caches Data for large operations such as Recovery Manager backup and restore activities and Shared Server Component.

Front 7

Describe Streams Pool?

Back 7

Caches the Data stored with Queued message request when Oracle Advance Queuing option is used.

Front 8

What is the unit of SGA memory space?

Back 8

Granules.
Granules can be 4MB, 8MB or 16MB Sizes.

Front 9

How many types of Parameter files are their?

Back 9

2 Types
1- PFILES Parameter Files
2- SPFILES Server Parameter Files.
Both of these files can be used to configure instance and database options including the size of SGA and its components if manual SGA management is being used.

Front 10

What are the differences between PFILE and SPFILE?

Back 10

PFILE:-
1- Its a text file
2- Instance need to be shutdown and restarted in order to get the changes.
3- Naming Convention initinstance name.ora
4- It can be created from SPFILE using create PFILE command.

SPFILE:-
1- its a binary file.
2- Most changes can be made dynamically when the instance is up and running.
3- The naming conventions are spfileinstance name.ora
4-Can be created from PFILE by using create SPFILE command.

Front 11

What dynamic performance view can be used to examine SGA?

Back 11

V$SGA
SQL>select * from V$SGA;
For looking into the SGA Components.
SQL>select components, current_size from v$sga_dynamic_components;