The init.ora/spfile parameter PGA_AGGREGATE_LIMIT got introduced in Oracle Database 12.1.0.1.
As per documentation in Oracle Database 12.1 it got defined as:
“PGA_AGGREGATE_LIMIT specifies a limit on the aggregate PGA memory consumed by the instance.“.
Furthermore the algorithm for its setting got described as:
“By default, PGA_AGGREGATE_LIMIT is set to the greater of 2 GB, 200% of PGA_AGGREGATE_TARGET, and 3 MB times the PROCESSES parameter. It will be set below 200% of PGA_AGGREGATE_TARGET if it is larger than 90% of the physical memory size minus the total SGA size, but not below 100% of PGA_AGGREGATE_TARGET.”
