In (PGA) Memory Sort Ratio

Sorts occur either in memory or in disk.

Memory - PGA (Faster no I/O involved)
Disk - Temporary Tablespace (Slower I/O involved)

This ratio indicates the amount of sorts performed in the Memory rather than on Disk.

OLTP database should have value greater than 95%.

If the value is less than 95%, then

• When not using Automatic PGA memory, then increase SORT_AREA_SIZE init parameter.
• When using Automatic PGA memory, then increase PGA_AGGREGATE_TARGET init parameter.

Run hitratio script to get the memory-sort ratio.

Thanks