Recommendation for PGA_AGGREGATE_TARGET in ASMM
Setting the Initial Value for PGA_AGGREGATE_TARGET


  To set the initial value for PGA_AGGREGATE_TARGET:
  
  
  Determine how much of the total physical memory to reserve for the
  operating system and other non-Oracle applications running on the same
  system.
  
  
  For example, you might decide to reserve 20% of the total physical
  memory for the operating system and other non-Oracle applications,
  dedicating 80% of the memory on the system to the Oracle database
  instance.
  
  
  Divide the remaining available memory between the SGA and the PGA:
  
  
  For OLTP systems, the PGA memory typically makes up a small fraction
  of the available memory, leaving most of the remaining memory for the
  SGA.
  
  
  
  Oracle recommends initially dedicating 20% of the available memory to
  the PGA, and 80% to the SGA. Therefore, the initial value of the
  PGA_AGGREGATE_TARGET parameter for an OLTP system can be calculated
  as:
  
  PGA_AGGREGATE_TARGET = (total_mem * 0.8) * 0.2 where total_mem is the
  total amount of physical memory available on the system.
  
  
  For DSS systems running large, memory-intensive queries, PGA memory
  can typically use up to 70% of the available memory.
  
  
  Oracle recommends initially dedicating 50% of the available memory to
  the PGA, and 50% to the SGA. Therefore, the initial value of the
  PGA_AGGREGATE_TARGET parameter for a DSS system can be calculated as:
  
  PGA_AGGREGATE_TARGET = (total_mem * 0.8) * 0.5 where total_mem is the
  total amount of physical memory available on the system.
  
  For example, if an Oracle database instance is configured to run on a
  system with 4 GB of physical memory, and if 80% (or 3.2 GB) of the
  memory is dedicated to the Oracle database instance, then initially
  set PGA_AGGREGATE_TARGET to 640 MB for an OLTP system, or 1,600 MB for
  a DSS system.