oracle启动各个状态下v$pgastat不同，why\？

NOMOUNT 下  v$pgastat

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
aggregate PGA target parameter                                    121634816 byte
aggregate PGA auto target                                                 0 byte
global memory bound                                                       0 byte
total PGA inuse                                                    14043136 byte
total PGA allocated                                                16059392 byte
maximum PGA allocated                                              16059392 byte
total freeable PGA memory                                                 0 byte
process count                                                            19
max processes count                                                      19
PGA memory freed back to OS                                               0 byte
total PGA used for auto workareas                                         0 byte

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
maximum PGA used for auto workareas                                       0 byte
total PGA used for manual workareas                                       0 byte
maximum PGA used for manual workareas                                     0 byte
over allocation count                                                     0
bytes processed                                                           0 byte
extra bytes read/written                                                  0 byte
cache hit percentage                                                      0 perc
recompute count (total)                                                   0

 

MOUNT  下 v$pgastat

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
aggregate PGA target parameter                                    121634816 byte
aggregate PGA auto target                                                 0 byte
global memory bound                                                       0 byte
total PGA inuse                                                    16214016 byte
total PGA allocated                                                30172160 byte
maximum PGA allocated                                              30172160 byte
total freeable PGA memory                                            983040 byte
process count                                                            20
max processes count                                                      20
PGA memory freed back to OS                                               0 byte
total PGA used for auto workareas                                         0 byte

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
maximum PGA used for auto workareas                                       0 byte
total PGA used for manual workareas                                       0 byte
maximum PGA used for manual workareas                                     0 byte
over allocation count                                                     0
bytes processed                                                           0 byte
extra bytes read/written                                                  0 byte
cache hit percentage                                                      0 perc
recompute count (total)                                                   0


OPEN  V$PGASTAT

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
aggregate PGA target parameter                                    125829120 byte
aggregate PGA auto target                                          27288576 byte
global memory bound                                                25165824 byte
total PGA inuse                                                    95593472 byte
total PGA allocated                                               117901312 byte
maximum PGA allocated                                             144396288 byte
total freeable PGA memory                                          12320768 byte
process count                                                            30
max processes count                                                      32
PGA memory freed back to OS                                        50855936 byte
total PGA used for auto workareas                                         0 byte

NAME                                                                  VALUE UNIT
---------------------------------------------------------------- ---------- ----
maximum PGA used for auto workareas                                 3172352 byte
total PGA used for manual workareas                                       0 byte
maximum PGA used for manual workareas                                     0 byte
over allocation count                                                     0
bytes processed                                                    24523776 byte
extra bytes read/written                                                  0 byte
cache hit percentage                                                    100 perc
recompute count (total)                                                  84