DB Parameter sizing for EBS

This post is for future reference and it is copied from oracle knowledge base.

Section 9: Database Initialization Parameter Sizing

This section provides sizing recommendations based on the active Oracle E-Business Suite user counts. The following table should be used to size the relevant parameters:

Parameter Name	Development or Test Instance	11-100 Users	101-500 Users	501-1000 Users	1001-2000 Users
processes	200	200	800	1200	2500
sessions	400	400	1600	2400	5000
sga_target Footnote 1	1G	1G	2G	3G	14G
shared_pool_size (csp)	N/A	N/A	N/A	1800M	3000M
shared_pool_reserved_size (csp)	N/A	N/A	N/A	180M	300M
shared_pool_size (no csp)	400M	600M	800M	1000M	2000M
shared_pool_reserved_size (no csp)	40M	60M	80M	100M	100M
pga_aggregate_target	1G	2G	4G	10G	20G
Total Memory Required Footnote 2	~ 2 GB	~ 3 GB	~ 6 GB	~ 13 GB	~ 34 GB

Footnote 1

• The parameter sga_target should be used for Oracle 10g or 11g or 12c based environments such as Release 12. This replaces the parameter db_cache_size, which was used in Oracle 9i based environments. Also, it is not necessary to set the parameter undo_retention for 10g or 11g or 12c-based systems, since undo retention is set automatically as part of automatic undo tuning.

• Enabling the 11g or 12c Automatic Memory Management (AMM) feature is supported in EBS, and has been found to be useful in scenarios where memory is limited, as it will dynamically adjust the SGA and PGA pool sizes. AMM is enabled by using the memory_target and memory_max_target initialization parameters. MEMORY_TARGET specifies the system-wide sharable memory for Oracle to use when dynamically controlling the SGA and PGA as workloads change. The memory_max_target parameter specifies the maximum size that memory_target may take. AMM has proven useful for small to mid-range systems as it simplifies both the configuration and management. However, many customers with large production systems have experienced better performance with manually sized pools (or large minimum values for the pools). On Linux, Hugepages has resulted in improved performance; however, this configuration is not compatible with AMM. For large mission-critical applications systems, it is advisable to set sga_target with a minimum fixed value for shared_pool_size and pga_aggregate_target.

Footnote 2

• The total memory required refers to the amount of memory required for the database instance and associated memory, including the SGA and the PGA. You should ensure that your system has sufficient available memory in order to support the values provided above. The values provided above should be adjusted based on available memory so as to prevent paging and swapping.

General Notes on Table

• "Development or Test instance" refers to a small instance used only for development or testing, with no more than 10 users.
  
• The range of user counts provided above refers to active Oracle E-Business Suite users, not total or named users. For example, if you plan to support a maximum of 500 active Oracle E-Business Suite users, then you should use the sizing as per the range 101-500 users.
  
• The parameter values provided in this document reflect a small instance configuration, and you should adjust the relevant parameters based on the Oracle E-Business Suite user counts as listed in the table above.
  
• The "csp" and "no csp" options of the shared pool parameters refer to the use of cursor_space_for_time, which is documented in the common database initialization parameters section.
   
  Note: Enabling cursor_space_for_time can result in significantly larger shared pool requirements.

References : 

Database Initialization Parameters for Oracle E-Business Suite Release 12 (Doc ID 396009.1)