What is Smon and Pmon?
PMON and SMON are two required background processes. PMON is the Process Monitor which is responsible for recovering processes when the user process fails. PMON does the process cleanup. SMON is the System Monitor which is responsible for recovering the system after a failure.
What is Oracle process architecture?
A client process runs the application or Oracle tool code. An Oracle process is a unit of execution that runs the Oracle database code. In the multithreaded architecture, an Oracle process can be an operating system process or a thread within an operating system process.
What are the components of Oracle architecture?
An Oracle instance consists of three main parts: System Global Area (SGA), Program Global Area (PGA), and background processes. The SGA is a shared memory structure allocated when the instance started up and released when it is shut down.
What is Pmon process in Oracle?
PMON (Process MONitor) is an Oracle background process created when you start a database instance. The PMON process will free up resources if a user process fails (eg. release database locks). PMON normally wakes up every 3 seconds to perform its housekeeping activities. PMON must always be running for an instance.
Which tasks are always performed by background processes in an Oracle database instance?
Oracle processes including the following subtypes: Background processes start with the database instance and perform maintenance tasks such as performing instance recovery, cleaning up processes, writing redo buffers to disk, and so on.
Which is the Oracle component that contains the memory structures and background process?
The SGA
The SGA is a group of shared memory structures, known as SGA components, that contain data and control information for one Oracle Database instance. All server and background processes share the SGA.
What is the difference between SGA and PGA?
Basic Memory Structures All server and background processes share the SGA. Examples of data stored in the SGA include cached data blocks and shared SQL areas. A PGA is a nonshared memory region that contains data and control information exclusively for use by an Oracle process.
What is difference between PGA and SGA?
A PGA is created by Oracle when a server process is started. The information in a PGA depends on the Oracle configuration. SGA (System Global Area) is an area of memory (RAM) allocated when an Oracle Instance starts up.
What is Oracle Database 11g architecture?
Oracle Database 11g Architecture Basically, there are two main components of Oracle database –– instance and database itself. An instance consists of some memory structures and the background processes, whereas a database refers to the disk resources. In this section, will cover the following topics related to the Oracle architecture:
What are the background processes in Oracle?
All components such as Log Writer (LGWR), DB Writer (DBWR), Checkpoint (CKPT), Recovery Process (RECO), Lock Process (LCKn), Archive Process (ARCH), System Monitor (SMON), and Program Monitor (PMON) are referred to as an Oracle Background processes.
What is F1 background process in Oracle Database?
F Background Processes. Table F-1 describes Oracle Database background processes. In this context, a background process is defined as any process that is listed in V$PROCESS and has a non-null value in the pname column. The External Properties column lists the type of instance in which the process runs.
In this post, you will learn about the ORACLE Architecture components such as Log Writer, DB Writer, etc (Background Processes), SGA, Buffer Cache, Shared Pool, etc (Memory Layout – Memory Buffer), Datafiles, Controlfiles, etc (Physical Oracle Layout). All these components, running together play an important part in the Oracle Architecture.