Program Global Area
Per-process or per-session private Oracle memory used for work areas, session state, stacks, and other process-specific data.
Oracle Runtime Context
The Program Global Area contains process- or session-private memory used for work areas, stacks, session state, and other private structures. Sorts, hash joins, and bitmap operations can spill to temporary storage when their work areas are too small.
Memory Boundary
PGA is not part of the shared SGA. Its private-memory role, work-area policies, process count, and spill behavior affect query latency and total host memory differently from shared cache sizing.