SGA_MAX_SIZE specifies the maximum size of the SGA for the lifetime of the instance.

Property Description

Parameter type

Big integer


SGA_MAX_SIZE = integer [K | M | G]

Default value

Initial size of SGA at startup, dependent on the sizes of different pools in the SGA, such as buffer cache, shared pool, large pool, and so on.



Modifiable in a PDB


Range of values

0 to operating system-dependent

On 64-bit platforms and non-Windows 32-bit platforms, when either MEMORY_TARGET or MEMORY_MAX_TARGET is specified, the default value of SGA_MAX_SIZE is set to the larger of the two parameters. This causes more address space to be reserved for expansion of the SGA.

On Windows 32-bit platforms, the default value of SGA_MAX_SIZE is the largest of the following values:

  • 60% of MEMORY_TARGET, if specified

  • 60% of MEMORY_MAX_TARGET, if specified

  • 25% of the total available virtual address space

See Also:

Oracle Database Performance Tuning Guide for more information about this parameter