ORA-02097,ORA-00384 error

Question

I want to use db_recycle_cache_size,I find the size of db_recycle_cache_size is 0,like follows:
SQL> show parameter db_recycle_cache_size
NAME TYPE VALUE
db_recycle_cache_size big integer 0
Then I use alter system command to resize db_recycle_cache_size,like follows:
SQL>alter system set db_recycle_cache_size=1M
ORA-02097:, parameter cannot be modified because specified value is invalid.
ORA-00384: Insufficient memory to grow cache To get around this problem
But I got above error. DB_BLOCK_SIZE is 8M and db_cache_size is 24M,there is enough memory space left,why I can't resize the value of db_recycle_cache_size? I have try many value of db_recycle_cache_size,all fail except 0 is success,why?
SQL>alter system set db_recycle_cache_size=1
ORA-02097:, parameter cannot be modified because specified value is invalid.
ORA-00384: Insufficient memory to grow cache To get around this problem
SQL>alter system set db_recycle_cache_size=0
success
SQL> show parameter DB_BLOCK_SIZE
NAME TYPE VALUE
db_block_size integer 8192
SQL> show parameter db_cache_size
NAME TYPE VALUE
db_cache_size big integer 25165824

Answer 1

Hi,
DB_BLOCK_SIZE is 8M aErrrr, nah, it's 8KiB :-)
ORA-02097:, parameter cannot be modified because specified value is invalid.Error message is self explanatory.. your value is wrong, but it's wrong because of:
ORA-00384: Insufficient memory to grow cache To get around this problemSo, as you're using db_recycle_cache_size, you're using 9i or 10g.
My first advice would be: you must read the concepts manual about:
. SGA_MAX_SIZE
. Dynamic memory pools
. Granule
Now, a little sample:TEST>SELECT * FROM V$VERSION WHERE ROWNUM=1;
BANNER                                                                                                                                                                             
Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production                                                                                                                   
TEST>SELECT DISTINCT GRANULE_SIZE/1024/1024 "The memory unit allocation" FROM V$SGA_DYNAMIC_COMPONENTS;
The memory unit allocation                                                                                                                                                         
                        16                                                                                                                                                         
TEST>SELECT COMPONENT, CURRENT_SIZE FROM V$SGA_DYNAMIC_COMPONENTS;
COMPONENT                                                        CURRENT_SIZE                                                                                                      
shared pool                                                         117440512                                                                                                      
large pool                                                                  0                                                                                                      
buffer cache                                                       5251268608                                                                                                      
TEST>SELECT LPAD(CURRENT_SIZE/1024/1024,5) || ' MiB' "Free space in memory" FROM V$SGA_DYNAMIC_FREE_MEMORY;
Free space in memory                                                                                                                                                               
    0 MiB                                                                                                                                                                          
TEST>-- So I got nothing available in memory!
TEST>-- In order to create the recycle cache, I will have to reduce the buffer cache size of 16M, in order to give the 16M to the recycle
TEST>
TEST>-- Or I'd get the same error as you
TEST>
TEST>ALTER SYSTEM SET DB_RECYCLE_CACHE_SIZE=16M;
ALTER SYSTEM SET DB_RECYCLE_CACHE_SIZE=16M
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00384: Insufficient memory to grow cache
TEST>SELECT 5251268608 / 1024 / 1024 FROM DUAL;
5251268608/1024/1024                                                                                                                                                               
                5008                                                                                                                                                               
TEST>SELECT 5008 - 16 FROM DUAL;
   5008-16                                                                                                                                                                         
      4992                                                                                                                                                                         
TEST>ALTER SYSTEM SET DB_CACHE_SIZE=4992M;
System altered.
TEST>-- Now, I got 16M of free memory
TEST>SELECT LPAD(CURRENT_SIZE/1024/1024,5) || ' MiB' "Free space in memory" FROM V$SGA_DYNAMIC_FREE_MEMORY;
Free space in memory                                                                                                                                                               
   16 MiB                                                                                                                                                                          
TEST>ALTER SYSTEM SET DB_RECYCLE_CACHE_SIZE=16M;
System altered.
TEST>-- Bingo!
TEST>spool offRegards,
Yoann.