Let's Learn Oracle Server Architecture

In this blog, let us learn about the architecture of Oracle Server. Oracle Server consists of 2 components, as follows:

  1. Oracle Database
    Oracle DB is further divided into physical & logical segments consisting of various locations, like files (Data file/Control File/Redo log file) in the physical segment, and Tablespace, Extent, Block, and Segment in the logical area.

  2. Oracle Instance
    Oracle instance consists of SGA (System global area) memory structure & background processes. An instance in Oracle indicates information stored in the database wherein the user can do all the changes as his/her own thoughts.



Instance is stored information in the DB, in which theuser accesses the data in an efficient manner. Instance gathers information of recently used queries in the DB via the shared pool, Buffer cache, Redo logbuffer cache, etc.


Stores recently used information in the Oracle DB via DataDictionary cache/Library cache.

DB Buffer cache

Writes the query in Data files/Control files via PMON (Process monitor-DBWR-DataBase writer)

Redo Log cache

Writes the query in Redolog files/Data files via checkpoint(ckpt-LGWR-Logwriter)