In a system, large online transaction processing (OLTP) jobs run during the daytime that require a large database buffer cache. In the night, the system supports batch jobs that require a higher…

Setting SGA_TARGET to zero disables ASMM entirely, reverting all SGA components to static manually specified sizes with no automatic rebalancing.

PRE_PAGE_SGA=TRUE causes Oracle to read all SGA pages into physical memory at instance startup to avoid page faults, but it does not enable any dynamic redistribution of memory between components.

Setting MEMORY_MAX_TARGET to zero disables Automatic Memory Management (AMM), which controls both SGA and PGA; setting it to zero would prevent AMM from functioning, not enable automatic SGA rebalancing.

Setting SGA_TARGET to a nonzero value activates Oracle's Automatic Shared Memory Management (ASMM), which continuously monitors workload demands and automatically resizes auto-tuned SGA components such as DB_CACHE_SIZE and LARGE_POOL_SIZE. During the day when OLTP workloads dominate, Oracle grows the buffer cache; at night during batch jobs, Oracle reallocates memory to the large pool. This eliminates the need for manual DBA intervention to reconfigure memory between operational modes.