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You're reading from  Oracle Database XE 11gR2 Jump Start Guide

Product typeBook
Published inJul 2012
Reading LevelIntermediate
PublisherPackt
ISBN-139781849686747
Edition1st Edition
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Author (1)
Asif Momen
Asif Momen
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Asif Momen

Asif Momen has been working with Oracle technologies for over 12 years and has expertise in Database Architecture, Performance Tuning, and High Availability. He has a Master's degree in Software Systems from Birla Institute of Technology & Science (BITS), Pilani. Asif is honored by the prestigious Oracle ACE award from Oracle Technology Network. He has the following certifications: OCP 11g DBA, OCP 9i Forms Developer and is an Oracle Certified Expert in RAC 10g. Asif is a presenter for conferences like Oracle OpenWorld-2010, All India Oracle User Group (AIOUG), and Brain Surface. In addition, he is the Member of Editorial Board of "Oracle Connect"the quarterly publication of AIOUG and Select magazine of the United Kingdom Oracle User Group (UKOUG) His articles have also appeared in Oracle Support - Customer Knowledge Exchange . His particular interests are Database & SQL tuning, Oracle RAC and Backup & Recovery. He posts his ideas and opinions on The Momen Blog (http://momendba.blogspot.com). Asif can be reached at asif.momen@gmail.com.
Read more about Asif Momen

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Memory structure


Oracle is available on almost every platform. For this reason, the physical architecture of Oracle is different on different operating systems. For example, on a Linux operating system, Oracle is implemented as multiple operating system processes whereas on Windows, Oracle is implemented as a single-threaded process.

Oracle uses memory to store information such as cached data, shared SQL and PL/SQL code, information about a session, and cursor pointers.

As mentioned earlier, Oracle memory structure is composed of two types of memory System Global Area and Process Global Area. The following sections will cover more on these topics.

System Global Area

System Global Area (SGA) is a large shared memory area that all server and background processes access. The SGA is broken into various pools as shown in the following diagram:

These pools are explained as follows:

  • Database buffer cache: This is where Oracle stores database blocks before writing them to the disk and after reading...

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Oracle Database XE 11gR2 Jump Start Guide
Published in: Jul 2012Publisher: PacktISBN-13: 9781849686747

Author (1)

author image
Asif Momen

Asif Momen has been working with Oracle technologies for over 12 years and has expertise in Database Architecture, Performance Tuning, and High Availability. He has a Master's degree in Software Systems from Birla Institute of Technology & Science (BITS), Pilani. Asif is honored by the prestigious Oracle ACE award from Oracle Technology Network. He has the following certifications: OCP 11g DBA, OCP 9i Forms Developer and is an Oracle Certified Expert in RAC 10g. Asif is a presenter for conferences like Oracle OpenWorld-2010, All India Oracle User Group (AIOUG), and Brain Surface. In addition, he is the Member of Editorial Board of "Oracle Connect"the quarterly publication of AIOUG and Select magazine of the United Kingdom Oracle User Group (UKOUG) His articles have also appeared in Oracle Support - Customer Knowledge Exchange . His particular interests are Database & SQL tuning, Oracle RAC and Backup & Recovery. He posts his ideas and opinions on The Momen Blog (http://momendba.blogspot.com). Asif can be reached at asif.momen@gmail.com.
Read more about Asif Momen