SGA_MAX_SIZE

Property	Description
Parameter type	Big integer
Syntax	`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	No
Range of values	0 to operating system-dependent

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

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 32-bit platforms, this can lead to a substantial reduction in address space usable for PGA. On these machines, workloads like data mining applications (where a single process uses large amounts of PGA) may result in error ORA-04030 with larger MEMORY_TARGET values.