PGA_AGGREGATE_TARGET
is the user workspace for Oracle users. By querying V$PGA_TARGET_ADVICE you can see what Oracle recommends on how to size your PGA_AGGREGATE_TARGET value. To query this view use the following query.SELECT round (PGA_TARGET_FOR_ESTIMATE/1024/1024) target_mb, ESTD_PGA_CACHE_HIT_PERCENTAGE cache_hit_perc, ESTD_OVERALLOC_COUNT FROM v$pga_target_advice;
The output
of this query will be similar to the
following:
TARGET_MB CACHE_HIT_PERC
ESTD_OVERALLOC_COUNT
----------
-------------- --------------------
24 15 143
48 32 28
95 42 4
143 63 0
From
the above results we should set the
PGA_AGGREGATE_TARGET
parameter to a
value where we avoid any over
allocation, so lowest
PGA_AGGREGATE_TARGET value we can
set is 143 (where
ESTD_OVERALLOC_COUNT is 0).
