Hi,
I have a 64G system that has about 24G set to pga_aggregate_target. I ran a huge query on about 500M rows of data and this is the outout of V$PGASTAT. Why is it that I see so little like 3G only allocated for "total PGA allocated" and so little "total PGA inuse". Since none of the other connections are doing anything I would expect oracle to use more PGA for sorting and has-joins right? Could some one please explain, thanks.
SQL> select * from V$PGASTAT;
NAME VALUE UNIT
---------------------------------------- ------------------------- ------------
aggregate PGA target parameter 25769803776 bytes
aggregate PGA auto target 22901907456 bytes
global memory bound 1073741824 bytes
total PGA inuse 3491868672 bytes
total PGA allocated 3630533632 bytes
maximum PGA allocated 3648694272 bytes
total freeable PGA memory 31850496 bytes
process count 42
max processes count 98
PGA memory freed back to OS 28158984192 bytes
total PGA used for auto workareas 3170180096 bytes
NAME VALUE UNIT
---------------------------------------- ------------------------- ------------
maximum PGA used for auto workareas 3435089920 bytes
total PGA used for manual workareas 0 bytes
maximum PGA used for manual workareas 531456 bytes
over allocation count 0
bytes processed 104064153600 bytes
extra bytes read/written 66399246336 bytes
cache hit percentage 61 percent
recompute count (total) 32614
19 rows selected.