Overview of Oracle database architecture

Oracle Database system is a complex software system. The Oracle architecture refers to the relationship between the components of the Oracle database management system and these components, including the memory structure, background process, physical and logical structure.

Overall diagram of the Oracle Database System:

 

The system of Oracle Database is complex because it saves memory to the maximum extent. It can be seen that it is divided into two parts: instance and database file.

I. Instance ):Refers to the memory and related processing programs of the database server. It is the heart of Oracle. The most important relationship with Oracle performance is SGA (System Global Area, which is the active shared memory Area in the System Global Area). SGA includes three parts:

1. Data Buffer to avoid repeated reading of common data;

2. The log buffer increases the speed of adding, deleting, and modifying data, and reduces disk read/write speed;

3. Share the pool to stop compiling the same SQL statement, improving the SQL Execution speed.

2. database files are composed of various file groups in the operating system.

1. Logical Structure of the Oracle database:

1) The tablespace, the basic logical structure of the database, is a collection of data files;

2) segments, the space occupied by different types of data in the database, which is composed of multiple zones;

3). The purpose of a zone is to reserve a large space for data at a time;

4). The minimum storage unit, which is specified when the database is created.

2. Physical Structure of Oracle Database:

1). Data File: The File that stores Data;

2) Redo Log File (Redo Log File), which records the processing status of any data in the database and can be used for data recovery;

3) Control File: controls and records the object structure of the database;

4) initialize the Parameter File and configure the memory space;

5). Password File to authenticate the user's permission to start and close Oracle routines.