You will examine the default settings for the default Oracle install and provide an estimation for the needed memory and disk space to support the required database. 

• Log into SQLPLUS at the DOS prompt.

SQLPLUS / AS SYSDBA

• Get the estimated SGA memory for your default install.

SELECT ROUND(SUM(VALUE)/1024/1024/1024) "TOTAL SGA (GiB)" FROM V$SGA;

• Get the estimated PGA memory for a database instance for your default database install with low process utilization.

SELECT ROUND(SUM(PGA_MAX_MEM)/1024/1024) "TOTAL MAX PGA (MiB)" FROM V$PROCESS;

• Get the maximum allocated for each user session for the default install.

SELECT ROUND(MAX(P.PGA_MAX_MEM)/1024/1024) "PGA MAX MEMORY OF USER SESSION (MiB)"

FROM V$PROCESS P, V$SESSION S

WHERE P.ADDR = S.PADDR AND S.USERNAME IS NOT NULL;                  

• Get the maximum number of processes that a database instance can manage for your default database install.

SELECT NAME, VALUE FROM V$PARAMETER

WHERE NAME = 'processes';

• Calculate the PGA memory for full process utilization using this formula. Round to the nearest GiB.

Total PGA = PGA low utilization

+ (Number of Processes * Max Allocated per Session)

• Calculate total RAM needed for the default install by using this formula. (an additional 20%  is needed for the OS). Round to the nearest GiB.

Default install RAM = (SGA + Total PGA) / 0.8

• Fill out the table below with the default install information.
• Calculate the required memory based on 5000 process/concurrent users. Use this formula. (For a ball park estimate SGA size equals PGA size) Round to the nearest GiB.

Estimated RAM needed

= 2 * (Number of Processes * Max Allocated per Session) / 0.8

• Fill out the table below with the estimated RAM needed information.
• Fill out the table below with the estimated database size. 

 

	SGA   (GiB)	PGA (low util) (GiB)	PGA  (high util) (GiB)	TOTAL  RAM (GiB)	TOTAL  DISK SPACE (GiB)
Default Install					N/A
Estimation		N/A