SGA_MAX_SIZE
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.

Parameter class Static

Range of values 0 to operating system-dependent


you can start adding up your buffer cache, shared pool, large pool, and so on parameters values and set your sga_max_size bigger than that

Oh btw the DB_CACHE_SIZE is db_block_buffer