DB_BUFFER_CACHE is static or not in Oracle10g v.2....?????

Question

Hi ,
I would like you to confirm if the database's buffer size area in SGA is static or dynamic according to the system needs....
I have somehow been blocked as :
SQL> select * from v$sga;
NAME                      VALUE
Fixed Size              1248600
Variable Size         125829800
Database Buffers 159383552
Redo Buffers            7139328In the above sql statement the database buffers are not included in the variable size of the sga.... so can it be assumed that it is a static component ..????
The above values are confirmed (they cannot be otherwise....) in the results of the following statement:
SQL> select * from v$sgainfo;
NAME                                  BYTES RES
Fixed SGA Size                      1248600 No
Redo Buffers                        7139328 No
Buffer Cache Size 159383552 Yes
Shared Pool Size                  109051904 Yes
Large Pool Size                     4194304 Yes
Java Pool Size                     12582912 Yes
Streams Pool Size                         0 Yes
Granule Size                        4194304 No
Maximum SGA Size                  293601280 No
Startup overhead in Shared Pool    37748736 No
Free SGA Memory Available                 0However , there is a table in the Oracle Admininistation e-book which titled "Automatically Sized SGA Components and Corresponding Parameters" and includes , among others , the Buffer Cache component......!!!!!
So , what is true......?????
They seem to be one contrary to the other....!!!!!
Thanks , a lot
Simon

Answer 1

Hi ,
I have just been blocked because in the followng sql statement:
SQL> select * from v$sga;
NAME                      VALUE
Fixed Size              1248600
Variable Size         130024104
Database Buffers      155189248
Redo Buffers            7139328The database buffers is not included in the variable size but in an individual section.....
However , as you have pointed out right executing the statement:
SQL> select * from v$sga_dynamic_components
  2  /
COMPONENT                                                        CURRENT_SIZE   MIN_SIZE   MAX_SIZE USER_SPECIFIED_SIZE OPER_COUNT LAST_OPER_TYPE LAST_OPER_MODE LAST_OPER_TIME GRANULE_SIZE
shared pool                                                         113246208  109051904          0                   0          1 GROW           IMMEDIATE      26/03/2007 18:      4194304
large pool                                                            4194304    4194304          0                   0          0 STATIC                                            4194304
java pool                                                            12582912   12582912          0                   0          0 STATIC                                            4194304
streams pool                                                                0          0          0                   0          0 STATIC                                            4194304
DEFAULT buffer cache                                                155189248  155189248          0                   0          1 SHRINK         IMMEDIATE      26/03/2007 18:      4194304
KEEP buffer cache                                                           0          0          0                   0          0 STATIC                                            4194304
RECYCLE buffer cache                                                        0          0          0                   0          0 STATIC                                            4194304
DEFAULT 2K buffer cache                                                     0          0          0                   0          0 STATIC                                            4194304
DEFAULT 4K buffer cache                                                     0          0          0                   0          0 STATIC                                            4194304
DEFAULT 8K buffer cache                                                     0          0          0                   0          0 STATIC                                            4194304
DEFAULT 16K buffer cache                                                    0          0          0                   0          0 STATIC                                            4194304
DEFAULT 32K buffer cache                                                    0          0          0                   0          0 STATIC                                            4194304
ASM Buffer Cache                                                            0          0          0                   0          0 STATIC                                            4194304The database buffers is a dynamic parameter.........if of course the automatic shared memory management is active.....
Thanks,
Simon